UC-NRLF 


hlfl    575 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


ELEMENTS 


CHEMISTRY, 


WITH 


PRACTICAL,  EXERCISES, 


ILLUSTRATED    BY 


on 


USE    OF    SCHOOLS 


BY     FRAXCIS     J.     GRUXD, 

Author  of  "  Elements  of  Natural  Philosophy,"  "  Elements  of  Plane  and 

Solid   Geometry,"    "  Popular    Lessons    in    Astronomy," 

'•  Exercises  in  Algebra,"  "  Arithmetic,"  etc. 


tion  and  object  of  Chemistry. 


BOSTON: 

CARTER,    HENDEE    AND    CO, 
1833. 


(hi 


Entered  according  to  act  of  Congress,  in  the  year  1833, 

BY  FRANCIS  J.  GRUND, 
in  the  clerk's  office  of  the  District  Court  of  Massachusetts. 


£75* 


PREFACE. 


IN  preparing  the  following  Elementary  Treatise  of 
Chemistry,  it  has  been  the  author's  particular  study  to 
form  a  proper  scientific  arrangement,  which  shall  enable 
the  learner  to  see  the  connexions  which  exist  between 
the  different  branches  of  the  natural  sciences,  and  to 
conduct  him  gradually  from  a  knowledge  of  the  sim- 
ple bodies,  or  elements  of  nature,  to  a  correct  under- 
standing of  their  more  complex  combinations. 

The  divisions  of  the  work,  it  is  believed,  will  be  found 
natural,  and  such  as  will  prove  a  strong  assistance  to 
the  memory. 

The  Introduction  contains  the  outlines  of  General 
Chemistry,  treating  separately, 

I.  Of  the  definition  and  object  of  Chemistry. 
II.  Of  Chemical  action. 

III.  Of  the  Chemical  apparatus,  and 

Of  the  Chemical  composition  of  bodies. 

The  first  four  chapters  may  be  considered  as  contain- 
ing the  elements  of  inorganic  chemistry.  The  first  treats 


iv  PREFACE. 

of  the  gaseous  elements  and  their  binary  combinations  ; 
the  second,  of  the  thirteen  non-metallic  elements  and 
their  binary  combinations ;  the  third  chapter  treats  sep- 
arately of  the  metals,  and  the  fourth  of  the  salts. 

To  the  description  of  each  element  is  annexed  a  short 
table,  exhibiting  its  principal  combinations  with  other 
substances,  and  each  chapter  is  followed  by  questions 
for  recapitulation,  which  are  numbered  to  correspond 
with  the  sections  of  the  book. 

The  fifth  and  sixth  chapters  treat  respectively  of 
vegetable  and  organic  chemistry,  and  the  seventh  chap- 
ter explains  the  three  principal  processes  of  fermentation, 
or  the  spontaneous  decomposition  of  organized  matter. 
Each  of  these  chapters  is  again  followed  by  questions 
for  review,  numbered  to  correspond  with  the  sections 
of  the  text.  The  appendix  contains  a  brief  description 
of  the  steam  engine,  with  questions  for  the  learner.  Nu- 
merous engravings  are  introduced  for  illustrating  the  ex- 
periments, and  indeed  no  expense  and  labor  spared  to 
render  the  work  intelligible  even  to  ordinary  capacities. 

It  is  hardly  necessary  to  add  that  on  his  tour  to 
Europe  the  author  has  had  an  opportunity  to  embody 
in  his  work  the  latest  discoveries  in  chemistry,  and  that 
it  may  therefore  be  reasonable  in  him  to  hope  that  in 
this  respect  his  book  is  not  inferior  to  any  similar  work 
published  in  this  country. 

BOSTON,  OCTOBER  1st,  1833. 


TABLE  OF   CONTENTS. 


INTRODUCTION. 

page. 

I.     Definition  and  Object  of  Chemistry,        .        /'•_ 

II.     Chemical  Action, 4 

III.  Chemical  Apparatus,        .  .         .         • 

IV.  Chemical  Composition  of  Bodies,       .        .      "  .•  .     .  36 

RECAPITULATION. 

I.     Questions  on  Definitions,      "Mr."      .         .  <(    .        j.  42 

II.       do.        on  Chemical  Action, 43 

III.  do.        on  Chemical  Apparatus,       ....  46 

IV.  do.        on  the  Chemical  Composition  of  Bodies,          .  48 

CHAPTER    I. 

Of  the  Properties  and  Combinations  of  the  Four  Gaseous  Elements, 
Oxygen,  Hydrogen,  Nitrogen,  and  Chlorine. 

A.  Oxygen, •    tV/--^:  *i;n  ^.  50 

Theory  of  Combustion,          .         .         .         »r.  •;,»,;      .  52 

B.  Hydrogen,          .         .         .         .         .             #  .j^^  59 

Properties  of  Hydrogen  gas, 61 

Combination  of  Hydrogens  with  Oxygen  —  Water,     .  73 

C.  Nitrogen  or  Azote, 87 

Combinations  of  Nitrogen  with  Oxygen,      ^  -^  u'*  " \  93 

do.             Nitrogen  with  Hydrogen,      .         .         .  101 

D.  Chlorine,            .         .         .- 103 

Combinations  of  Chlorine  with  Oxygen,         •  '   /  •    •'-*•    •  104 

do.                 do.        with  Hydrogen,          .      :  .'  106 

do.                 do.        with  Nitrogen,       .i^i^i^P  .  109 

RECAPITULATION. 

Questions  for  Reviewing  some  of  the  most  important  Principles 
contained  in  the  1st  Chapter. 

A.  Questions  on  Oxygen,        .         .       v^I'l  j*>  i^sfiV~:^.  1^ 

B.  do.      on  Hydrogen,        .         .  '      «        T        ;    ~   .  112 

»# 


vi  CONTENTS, 

C.  Questions  on  Nitrogen,      .        .        .        .        .        .         116 

D.  do.       on  Chlorine, 120 

CHAPTER    II. 

Of  the  remaining  nine  Non-metallic  Elements,  and  their 
combinations, 122 


A. 

Carbon,      

122 

Combinations  of  Carbon  with  Oxygen, 

.     125 

do.                 do.        do.    Hydrogen, 

129 

do.                do.       do.    Nitrogen, 

.     134 

do.       of  Cyanogen  with  Oxygen, 

135 

do.                do.          do.   Hydrogen,    . 

.     135 

Other  combinations  of  Cyanogen, 

138 

Combinations  of  Carbon  with  Chlorine, 

.     138 

do.                do.       do.    Sulphur, 

139 

B. 

Sulphur,        

.     141 

Combination  of  Sulphur  with  Oxygen, 

142 

do.                do.          do.    Hydrogen,     . 

.     147 

C. 

Silenium,            ...... 

149 

D. 

Phosphorus,           

.     149 

Combinations  of  Phosphorus  with  Oxygen, 
do.                    do.           do.    Hydrogen, 

151 
.     152 

E. 

Boron,        

155 

.     155 

F. 

Iodine,   .         .             .         .         .         »".'../' 

'.'*:?.         156 

Combination  of  Iodine  with    Oxygen, 

157 

do.               do.       do.     Hydrogen, 

.     157 

G. 

Bromine,    ....... 

158 

Combinations  of  Bromine,      .... 

.     159 

H. 

Silicon,      ....... 

159 

Combinations  of  Silicon  with  Oxygen,   . 

.     160 

Properties  of  Silex,    

160 

I. 

Fluorine,        

.^     .     162 

-i'-T  ••  V.         162 

Other  combinations  of  Fluorine, 

163 

RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles  contained 
in  Chapter  II. 

A.  Questions  on  Carbon, 164 

B.  Questions  on  Sulphur,  ......  167 

C.  Questions  on  Silenium,       ......  169 

D.  Questions  on  Phosphorus, 169 

E.  Questions  on  Boron, 171 

.  F.     Questions  on  Iodine,      .  .  171 

G.     Questions  on  Bromine, 172 

H.    Questions  on  Silicon,     . 172 

I.      Questions  on  Fluorine,       ,         .         .        .         .       '«  173 


.     CONTENTS.  Vll 

CHAPTER    III. 
OF     THE     METALS. 

Preliminary  remarks,            .        .        .                 .         .        .  174 

Jj.     Of  the  six  Alkaline    Metals,   Potassium,   Sodium, 

Lithium,    Calcium,  Barium,  and  Strontium,           .        .  180 

1.  Potassium,             180 

Combinations  of  Potassium, 183 

2.  Sodium, 185 

Combinations  of  Sodium, 185 

3.  Lithium, 186 

Combinations  of  Lithium, 187 

4.  Calcium, 187 

Combinations  of  Calcium, 187 

5.  Barium, 188 

Combinations  of  Barium, 188 

6.  Strontium, 189 

Combinations  of  Strontium,            .....  189 

B.  Of  the  six  Earthy  Metals,  Magnesium,  Yttrium,  JLlumi- 
um,  Glucinum,   Zirconium,  and    Thorium.            .         .  190 

1.  Magnesium 190 

Combinations  of  Magnesium, 191 

2.  Glucinum, 192 

Combinations  of  Glucinum,        .....  192 

3.  Yttrium, 193 

Combinations  of  Yttrium,            .....  193 

4.  Alumium, 193 

Combinations  of  Alumium, 193 

5.  Zirconium 194 

Combinations  of  Zirconium, 194 

6.  Thorium, 195 

Combinations  of  Thorium, 195 

C.  Of  the  nine  Noble  Metals,  Mercury,  Silver,  Gold,  Plati- 
num, Palladium,  Rhodium,  Iridium,  Osmium.,  and  Nickel,  195 

1.  Mercury, •  195 

Combinations  of  Mercury  with  Oxygen,       .         .         .  196 

do.                do.          do.     Chlorine,           .        .  197 

do.                 do.          do.     Sulphur,       .         .         .  199 

2.  Silver, 200 

Combinations  of  Silver, 200 

3.  Gold, 202 

Combinations  6f  Gold,             203 

4.  Platinum,           .  .  ,:f; 204 

5.  Palladium,       .         *'.?:>'.. "/  »; 206 

6.  Rhodium, 207 

7.  Iridium,                             , 207 

8.  Osmium,       .                           207 

9.  Nickel,            . 208 


X  CONTENTS. 

7.  Carbonate  of  Lead,        .        .        .        .        .        .  283 

8.  do.            Iron, 284 

9.  do.            Copper, 284 

G.     Phosphates, 234 

1.  Phosphate  of  Ammonia, 285 

2.  do.            Soda, 285 

3.  do.            Lime, 286 

H.     Chromates, 286 

1.  Chromate  of  Potash, 287 

2.  do.            Lead, 287 

3.  do.            Mercury,           .  287 
I.    Jlrseniates  and  JLrsenites, 287 

1.  Arsenite   of  Potash, 288 

2.  do.             Cobalt, 288 

J5f.     Cyanites  and  Fulminates, 288 

RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles  contained 
in  Chapter  IV. 

I.      Questions  on  the  General  Remarks  on  the  salts  and  acids,  289 

Questions  on  Crystalography, 291 

A.  Questions  on  the  Nitrates, 292 

B.  Questions  on  the  Chlorates, 293 

C.  Questions  on  the  Chlorides, 294 

E.  Questions  on  the  Sulphates, 295 

F.  Questions  on  tiie  Carbonates, 296 

G.  Questions  on  the  Phosphates, 298 

H.    Questions  on  the  Chromates, 298 

I.      Questions  on  the  A rseniates  and  A  rsenites,   .         .         .  299 

K.    Questions  on  the  Fulminates, 299 

CHAPTER   V. 

VEGETABLE  CHEMISTRY. 

General  Remarks  on  the  Difference  between  Organic  and  In- 
organic matter,        .         . 300 

I.     UNSALIFIABLE  VEGETABLE  SUBSTANCES,        .         .  303 

A.  Neutral  Unsaleable   Vegetable  Substances,        ,  304 

1.  Woody  Fibre,        ...         ;         ...  304 

2.  Starch, 304 

3.  Gum,  or  Mucilage, 305 

4.  Sugar, 305 

B.  Watery,  Unsaleable  Vegetable  Substances,    .         .  306 

1.  Volatile  or  essential  oils, 306 

2.  Fat  or  fixed  oils, 307 

3.  Resins, 308 

4.  Wax,      . 309 

5.  Alcohol,      ....              '"V      •  .       -'.  309 

6.  Ether  and  Naphta,         .         .         .         .:      .  .,* .  310 


.     CONTENTS.  XI 

II.  SALIFIABLE  VEGETABLE  BASES,          ...  311 

III.  VEGETABLE  ACIDS, .  312 

A.  Fixed  Vegetable  Acids, 312 

1.  Tartaric  acid, 312 

2.  Citric  acid,          ...;...  313 

3.  Malic  acid,     .        .    •     .        .        .         .        .         .313 

4.  Oxalic  acid, 314 

5.  Gallic  acid, 314 

6.  Vegetable  Jelly,  or  Pectic  acid,           .         .         .  314 

7.  Bitumous  acid, 315 

B.  Vegetable  Acids  capable  of  Sublimation,      ,        .  315 

1.  Benzoic  acid, 315 

2.  Succinic  acid, 316 

3.  Boletic  acid,  .         .         .         .         .         ,         .         .316 

C.  Liquid  Vegetable  Acids  (capable  of  Distillation),  316 
1., Acetic  acid, 316 

2.  Prussia  acid,  .         .        ..         .         .         .         .318 

3.  Cyanic  acid, 318 

IV.  VEGETABLE  SUBSTANCES  OF  AN  UNDETERMINED 

NATURE, '.f.     \.  318 

1.  Coloring  matters,           .         .'       ,        -.        ;v -•-'..  318 

2.  Vegetable  extracts,     .     :/vrv.r5.       •:„,:<-  ;"'••;. N 

3.  Fennentous  principles,           .         .         .         *         ;  320 

a.  Lees  (dregs), 320 

b.  Vegetable  albumen, 321 

.  c.  Gluten, 321 

RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles  Contained 
in  Chapter   V. 

A.     Questions  on  the  general  remarks  on  the  difference 

between  organic  and  inorganic  bodies,      vc.  •  ,  •  .  322 

Questions  on  the  unsalifiable  vegetable  substances,       .         .  323 

Questions  on  the  salifiable  vegetable  substances,       .         .  325 

Questions  on  the  vegetable  acids,          .         .         .         .         .  325 

Questions  on  vegetable  substances  of  aji  undetermined  nature,  327 

CHAPTER  VI. 

ANIMAL  CHEMISTRY,      .  ri**  or -••:         .         .         .  329 

1.  Animal  Jelly  (Glue),     ....    *-;,,:.%;•  331 

2.  Albumen, .  331 

3.  Blood, 332 

Chemical  changes  in  the  nature  of  Blood,  occasioned 

by  Respiration, 333 

4.  Of  the  Milk, 333 

5.  Butter, .  334 

6.  Cheese, 334 

7.  Sugar  of  milk,   .                ,                ,     ...  , .     ,.f       .  335 


XII  CONTENTS. 

8.  Animal  mucus, 335 

9.  Animal  oils  and  fats, 335 

10.  Animal  acids, 336 

a.  Olific  acid, 336 

6.  Lactic  acid, 337 

d.  Mucous  acid, : 

e.  Formic  acid,        .                  337 

11.  Of  the  different  liquids  employed  in   the   process  of 

digestion, 338 

a.    Saliva, 338 

6.    Gastric  juice 338 

c.    Bile, 338 

12.  Of  the  Chyle, 339 

13.  Substance  of  the  Brain  and  Nerves,       .         .         .         .340 

14.  Fibrin, 341 

15.  Of  the  Bones,  Teeth,  and  Cartilage,       .         .        .         .341 

16.  Of  the  Marrow, 342 

17.  Of  the  Muscles,  Membranes,  Ligaments  and  Tendons,   .  342 

18.  Coverings  of  animals, 343 

a.    Of  the  skin,  .        .         .   .     .        .        .        .343 

6.    Nails,  Claws,  Horns,  Hoofs,  Scales,  &c,    .         .  343 

e.    Hair,  Bristles,  Feathers,  Wool,  and  Silk,      .         .  344 

RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles  con- 
tained in  Chapter  VI,  .        .        .       ,v  •    ...  845 

CHAPTER  VII. 

Of  the  Chemical  Process  accompanying  the  Development,  Life, 
and  Death  of  Organized  Bodies. 

A.  Germination  of  seeds.      .                351 

B.  Process  of  Nutrition  necessary  to  life,         .         .         .  351 

C.  Of  the  spontaneous  decomposition  of  Organic  substances,  352 

1.  Vinous  Fermentation,         .  352 
Phenomena  accompanying  vinous  fermentation,     .  353 

2.  Acetous  Fermentation, 354 

3.  Of  the  process  of  Putrefaction,       ....  355 
Putrefaction  with  free  access  of  air,   .         .         .  356 
Putrefaction  with  little  or  no  access  of  air,    .        .  356 

RECAPITULATION. 

Containing  Questions  for  Reviewing  Chapter  VII.  .        .  357 

APPENDIX. 

On  the  steam  engine, 360 

Questions  on  the  steam  engine, 371 


CHEMISTRY. 


INTRODUCTION. 


I.     DEFINITION  AND  OBJECT  OF  CHEMISTRY. 

I.  ALL  natural  sciences,  that  is,  all  human  knowledge 
about  created  nature,  may  be  divided  into  two  great  classes 
—  Natural  History,  and  Natural  Philosophy. 

II.  Natural  History  has  for  its  object  the  systematic 
description  of  animate  and  inanimate  (living  and  lifeless) 
bodies,  and  is  again  divided  into  Zoology,  Botany,  and 
Mineralogy  ; :  according  as  the  bodies  described  are  Ani- 
mals, Plants,  or  Minerals. 

III.  The  object  of  Natural  Philosophy  is  to  explain 
the  various  phenomena  which  occur  in  the  material  world, 
by  finding  out  their  mutual  relation  and  connection  with 
certain    invariable    principles,    called    Laws  of  Nature. 
The  phenomena,  themselves,  may  have  their  origin  in  the 
general  properties  of  matter  ;  such  as  gravity,  attraction, 
elasticity,  &c,*  and  consist,  then,  principally  in  motion  ; 
or  they  may  be  occasioned  also  by  certain  powers  which 
are  inherent  in  bodies,  by  virtue  of  which  one  body  changes 
the  form  and  properties  of  another  with  which  it  comes  in 
contact.     On  this  account  Natural  Philosophy  has  been 
divided  into  two  great  branches  ;  one  which  treats  of  the 
Mechanical  properties    of   matter  —  Natural  Philosophy 

*  See  Grund's  Elements  of  Natural  Philosophy. 
1 


CHEMICAL     ACTION. 


This  double   composition   is  exhibited  by  the  following 
*«ki~ 


table. 

Saltpetre. 


nitric  acid,  alkali. 


nitrogen,  oxygen,  potassium,        oxygen. 

Query.  — Which,  in  this  example,  are  the  nearer,  and  which 
the  more  remote  ingredients  of  saltpetre  ?  J)ns.  —  In  this  ex- 
ample nitric  acid  and  alkali  are  the  nearer  ;  nitrogen,  potassium, 
and  oxygen,  the  more  remote  ingredients  of  saltpetre. 

VIII .  Those  substances  which  have  not  as  yet  been 
decomposed  by  any  means  in  our  power  are  called  Ele- 
ments ;  but  it  does  not  follow  that  all  substances  which  are 
now  considered  as  elements,  are  really  incapable  of  chem- 
ical analysis. 

Query.  —  What  then  does  the  word  Element  express  in 
chemistry  ?  Ans.  —  The  word  Element  indicates  only  the 
degree  of  our  knowledge  with  regard  to  a  certain  substance, 
and  shows  that  we  have  not,  as  yet,  been  capable  to  decom- 
pose this  substance. 


II.     CHEMICAL  ACTION. 

IX.  It  has  been  observed  that  each  chemical  composi- 
tion or  decomposition,  in  other  words,  all  chemical  action, 
is  effected  by  a  peculiar  kind  of  attraction,  called  affinity. 
This,  therefore  must  be  considered  as  the  principal  cause  of 
all  chemical  phenomena. 

The  changes  produced  on  bodies  which  are  subjected  to 
it,  are  principally  the  following. 

a.    A  change  in  temperature. 

EXAMPLE.  —  Oil  of  vitriol  and  water  suddenly  mixed,  pro- 
duce a  temperature  of  212°  Fahrenheit:  —  Again,  Salammo- 
niac  and  snow  mixed  together,  produce  a  cold  equal  to  zero  of 
Fahrenheit's  thermometer. 

Hence  chemical  affinity  changes  the  capacity  for  heat, 
or  the  specific  caloric  of  bodies.  (Nat.  Phil.  Chap.  VI.) 


C.HEMICAL    ACTION.  5 

b.  A  change  in  the  physical  properties  of  bodies. 

EXAMPLE.  —  Sulphur  and  oxygen  are  both  destitute  of  smell, 
taste,  or  action  on  vegetable  color  ;  but  when  combined  to- 
gether they  form  a  powerful  acid,  of  a  strong  smell,  which 
changes  blue  vegetable  colors  into  red. 

ANOTHER  EXAMPLE.  — Quicksilver,  which  is  of  a  bright  tin- 
color,  unites  with  sulphur,  which  is  yellow,  and  forms  a  sub- 
stance called  cinnaber,  distinguished  by  its  beautiful  red  color. 

c.  Change  in  the  aggregate  form  of  bodies* 
EXAMPLE.  —  Oxygen  and  hydrogen  are  both  aeriform,f    or 

gaseous,  but  when  combined  in  the  ratio  of  about  1  to  8,  form 
the  well-known  liquid,  water. 

It  is  not  unfrequent  to  see  chemical  action  accompanied  by 
light.  The  intensity  of  this  light  increases  with  the  degree 
of  affinity  which  exists  between  the  two  combining  bodies,  and 
the  circumstances  which  favor  their  combination.  This  phe- 
nomenon will  be  explained  in  Chap.  I,  when  treating  of  oxy- 
gen. 

X.  It  becomes  us  to  speak  separately  of  the  great  influ- 
ence which  heat  has  upon  all  chemical  phenomena.  And 
this  is  not  only  so  far  true,  that  no  chemical  action  takes 
place  without  a  change  of  temperature ;  but  is  founded  also 
on  the  fact  that  some  combinations  or  decompositions  are. 
effected  only  through  the  influence  of  higher  degrees  of  tem- 
perature (when  one  or  the  other  body  has  previously  been 
heated.)  Heat,  therefore  is  a  powerful  chemical  agent, 
which,  in  most  cases,  favors  the  chemical  affinity  of  one 
body  for  another  ;  although  there  are  instances  in  which 
heat  seems  to  produce  a  different  effect. 

EXAMPLE.  —  The  process  of  fermentation  and  putrefaction 
(see  Chapter  VII)  requires  at  least  32  degrees  Fahrenheit. 

dgain  —  Quicksilver  combines  with  oxygen  only  when 
heated  to  2 12  degrees;  and  the  result  of  this  combination, 
which  is  the  oxide  of  quicksilver,  separates  again  into  quicksil- 
ver and  oxygen,  when  submitted  to  a  red  heat. 

ANOTHER  EXAMPLE.  —  The  Chloratts,  a  class  of  salts  with 
which  we  shall  hereafter  become  acquainted,  are  decomposed 

*  See  Natural  Philosophy,  Chapter  I, 
t  See  Natural  Philosophy, 
1* 


6  C.HE  MI  CAL     ACTION. 

and  give  off  the  oxygen  which  they  contain,  when  thrown 
upon  live  coals. 

XI.  The  greatest  obstacle  to  chemical  action  is  the  co- 
hesive   attraction  of  bodies  ;  —  that  is,  (as  has  been  ex- 
plained in  Natural  Philosophy)  the  attraction  by  which  their 
particles  are  kept  together  and  in  their  relative  positions.* 
This  is  the  reason  why  bodies  combine  readiest  with  each 
other,  when  one  or  the  other  has  been  reduced  to  the  fluid 
state ;    because  the  cohesive  attraction  is  less  in  liquids 
than  in  solid  substances.     It  also  explains  why  heat  in- 
creases the  action  of  chemical  affinity  ;  because  heat,  by 
expanding  all   bodies    (Natural'  Philosophy,   Chap.   VI,) 
lessens  their  cohesive  attraction,  and  predisposes  them  for 
the  fluid  state.     From  this  the  general  inference  has  been 
drawn,  that  no  chemical  action  takes  place,  except  one  of  the 
two  bodies  is  in  the  fluid  state.     This  rule,  however,  is  not 
without  exceptions. 

Query  —  What  would  take  place  if  there  were  no  cohesive 
attraction  to  counteract  the  chemical  affinities  of  bodies  ? 
Ans.  —  Without  the  cohesive  attraction  of  the  particles  of 
bodies,  all  substances  would  combine  and  unite  with  each  oth- 
er to  one  huge  mass. 

Query  —  How,  then,  must  chemical  affinity  and  cohesive  at- 
traction be  considered  in  reference  to  each  other  ?  Ans.  — 
They  must  be  considered  as  two  opposite  powers  in  nature 
whose  effects,  by  a  wise  distribution  of  Providence,  are  won- 
derfully balanced. 

XII.  Bodies  frequently  combine  with  each   other  in 
such  a  way  that  each  of  them  loses  its  physical  properties 
in  the  combination.     They  are  then  said  to  be  neutralized. 

In  the  above  example,  the  oxygen  and  the  sulphur  are 
neutralized  in  sulphuric  acid. 

ANOTHER  EXAMPLE.  —  Alkali  (potash)  and  sulphuric  acid 
are  each  distinguished  by  a  peculiar  taste  ;  potash  changes 
blue  vegetable  colors  into  green,  and  sulphuric  acid  turns 
them  into  red.  By  mixing  these  substances  in  the  proper 
proportion,  we  obtain  a  salt  destitute  of  either  acid  or  alka- 
line qualities ;  its  taste  being  bitter,  and  the  salt  itself  be- 
ing without  any  effect  on  vegetable  colors. 

*  See  Natural  Philosophy,  Chapter  I. 


CHEMICAL    ACTION.  7 

Query  —  In  what  state  are  the  potash  and  the  sulphuric 
acid,  in  this  case,  contained  in  the  salt?  JJns. — They  are 
neutralized  in  it. 

It  may  be  well  to  observe  here,  that  in  order  to  effect  a 
complete  neutralization,  the  two  bodies  must  combine  in  a 
certain  fixed  proportion,  before  or  beyond  which  no  such  phe- 
nomenon takes  place. 

XIII.  Some  bodies  combine  with  each  other  in  all  pro- 
portions, and  preserve  still   a  portion  of  their  original 
properties.     Such  a  combination  is  more  properly  called  a 
mixture. 

EXAMPLE.  —  If  wine  and  water  be  poured  together,  a  mix- 
ture is  obtained  in  which  the  fluidity  of  both  liquids,  as  well 
as  some  of  the  taste  and  color  of  the  wine  is  preserved.  The 
same  is  the  case  when  vinegar  and  water,  alcohol  and  water, 
alcohol  and  wine,  &c,  are  poured  together. 

XIV.  Whenever  we  wish  to  decompose  a  chemical  com- 
pound into  its  constituent  parts,  we  must  have  recourse  to 
a  third  substance,  with  which  one  of  these  parts  is  to  com- 
bine, by  which  means  the  other  becomes  disengaged  or  free. 
This  kind  of  chemical  attraction,  in  consequence  of  which 
a  body  quits  a  combination  already  existing,  for  the  sake  of 
forming  a  new  one,  is  called   Elective  affinity;   because 
the  body  seems,  as  it  were,  to  elect  one  combination  in 
preference  to  another,  which  it  has  already  formed. 

EXAMPLE.  —  Muriate  of  lirne  is  a  compound  of  muriatic  acid 
and  lime  ;  but  when  potash  is  added  to  the  solution  the  muri- 
atic acid  combines  with  the  potash,  and  the  lime  being  now- 
disengaged  falls  to  the  bottom,  and  forms  what  is  called  a 
precipitate.  This  process  may  be  represented  to  the  eye  by 
the  following  figure. 

Muriate  of  Potash. 


C     Muriatic  acid.  Potash, 

Muriate  of  Lime.  < 

(|     Lime. 

The  original  compound  (Muriate  of  Lime)  is  composed  of 
Muriatic  acid  and  lime.  As  soon  as  potash  is  added,  the  mu- 
riatic acid  combines  with  the  potash,  and  forms  muriate  of  pot- 
ash ;  and  the  lime  becomes  free, 


CHEMICAL    ACTION. 

Query  —  What  substance,  in  this  example,  shows  an  elect- 
ive affinity  for  Potash  ?  Jlns.  —  The  muriatic  acid.  Query  — 
Why  ?  Ans.  —  Because  it  quits  its  combination  with  lime, 
and  unites,  as  it  were,  in  preference  with  the  potash. 

XV.  When  a  solid   body  combines  with  a  fluid,  the 
product  is  called  a  solution.     In  this  case  the  affinity  be- 
tween the  two  substances  continues  to  act  only  to  a  certain 
point,  that  is,  the   liquid  is  only  capable  to   dissolve  a  cer- 
tain portion  of  the  solid  — so  that  if  we  wished  to  have  a 
greater  quantity  of  the  solid  dissolved,  we  should  have  to 
add  more  of  the  liquid.    The  point  beyond  which  the  affin- 
ity of  the  liquid  ceases  to  act  upon  the  solid,  is  called  the 
point  of  saturation ;  and  the  solution  itself,  when  arrived 
at  this  point,  is  said  to  be  saturated. 

EXAMPLE  —  Water  will  dissolve  only  a  certain  quantity  of 
sugar  or  salt,  until  it  becomes  saturated.  A  fresh  quantity 
of  sugar  or  salt  being  then  added  will  remain  unchanged  at 
the  bottom  of  the  vessel.  But  if  a  new  quantity  of  water  be 
added  to  the  solution,  then  a  new  quantity  of  sugar  or  salt 
will  be  dissolved. 

XVI.  The  saturation  of  liquids  depends  principally  — 

1.  Upon  the  temperature  of  the  liquid. 

2.  Upon  the  degree  of  affinity  which  exists  between  the 
liquid  and  the  solid  ;  and 

3.  Upon  the  purity  of  the  liquid. 

The  warmer  the  liquid  is,  the  more  can  it  generally  dis- 
solve of  a  given  solid.  To  this  rule,  however,  there  are 
several  exceptions. 

EXAMPLE.  —  Water  of  the  temperature  of  212°  Fahrenheit, 
will  dissolve  no  more  common  salt,  than  water  of  the  tempera- 
ture near  the  freezing  point.  Water  of  the  temperature  of 
212°  dissolves  even  less  magnesia,  than  water  of  the  common 
temperature  of  the  atmosphere.  But  with  regard  to  most 
salts  the  solving  power  of  water  increases  with  the  tempera* 
ture. 

XVII.  It  frequently  occurs  that  a  compound  of  two 
substances  cannot  be  decomposed  without  the  assistance 
of  a  third  and  fourth  substance.      The  affinity  of  the 
third  substance  for  any  one  of  the  constituent  parts  of  the 


CHEMICAL    ACTION.  9 

compound,  is  then,  of  itself,  not  sufficient  to  produce  a  sep- 
aration. This  kind  of  affinity  is  called  Double  or  Complex 
affinity.  It  will  be  best  understood  from  the  following 

EXAMPLE. 

Zinc  decomposes  water  (which  is  a  compound  of  oxygen 
and  hydrogen)  only  when  an  acid  is  added.  The  hydro- 
gen of  the  water  then  becomes  free,  while  the  zinc  and 
oxygen  combine  together  with  the  acid  to  form  a  salt.  — 
The  zinc,  of  itself,  is  not  capable  of  separating  the  oxygen 
from  the  hydrogen  ;  but  the  acid  having  a  strong  affinity 
for  a  combination  of  zinc  and  oxygen,  predisposes  the  oxy- 
gen to  quit  its  combination  with  water  and  to  combine  with 
the  zinc.  For  an  illustration,  see  the  following  table  : 

(  hydrogen, 
Water,      J 

(    oxygen, 


>xygen,   } 

>   oxide  of  zinc,  1 
zinc,        )  \  salt, 

acid  ) 


Zinc  alone  does  not  separate  the  oxygen  from  the  hy- 
drogen; but  when  the  acid  is  added,  which  has  a  strong 
affinity  for  the  oxide  of  zinc,  this  latter  substance  (oxide  of 
zinc)  is  formed,  and  combines  with  the  acid  to  salt. 

Some  philosophers  ascribe  these  phenomena  to  a  predispos- 
ing affinity  ;  because  the  acid,  in  our  first  example,  seems  to 
predispose  the  oxygen  for  a  combination  with  the  zinc. 

Query  —  What  substance,  in  this  example,  has  exercised 
a  predisposing  affinity  upon  oxygen?  Jlns.—  The  acid. 
Query  —  Why  ?  Jlns.  —  Because  it  has  disposed  it  for  a 
combination  with  the  zinc.  Query  —  But  by  what  means  doea 
the  acid  predispose  the  oxygen  for  a  combination  with  the 
zinc  ?  Jlns.  —  By  the  strong  affinity  which  it  has  for  the 
oxide  of  zinc,  which  is  a  combination  of  the  oxygen  with 
zinc. 

XVIII.  If  two  compounds  be  brought  together  in  a 
state  of  solution,  it  frequently  happens  that  a  double  de- 
composition, and  two  new  compositions  take  place.  Both 
the  original  compounds  are  then  decomposed,  and  two  new 
compositions  are  formed  by  a  mutual  interchange  of  in- 
gredients. Such  a  compound  action  is  said  to  be  caused 
by  double  elective  affinity. 


10  CHEMICAL    ACTION. 

EXAMPLE. — The  well  known  substance,  sugar  of  lead, 
(which  is  used  as  a  paint)  is  composed  of  acetic  acid  (vinegar) 
and  lead.  White  vitriol  is  a  compound  of  sulphuric  acid  and 
zinc.  Now  if  a  solution  of  sugar  of  lead  be  mixed  with  a  so- 
lution of  white  vitriol,  the  acetic  acid  will  quit  its  combination 
with  lead,  and  unite  with  the  zinc  ;  while,  at  the  same  time, 
the  sulphuric  acid  which  is  set  free,  unites  with  the  lead  and 
forms  an  insoluble  hard  powder  (sulphate  of  lead)  which 
is  precipitated.  For  an  illustration  see  the  following  dia- 
gram. 

Acetate  of  zinc, 

C  Acetic  acid,  Zinc,      } 

Sugar  of  Lead,  3  V  White  Vitriol, 

(  Lead,  Sulphuric  acid,  ) 


Sulphate  of  lead. 

The  original  compounds,  sugar  of  lead  and  white  vitriol,  are 
placed  at  the  extremities  of  the  two  brackets  ;  their  respective 
ingredients,  acetic  acid  and  lead,  and  zinc  and  sulphuric  acid, 
are  placed  inside  of  the  brackets  ;  the  new  compounds,  ace- 
tate of  zinc,  which  is  formed  by  the  combination  of  the  acetic 
acid  with  the  zinc  is  placed  above  the  upper,  and  the  second 
compound,  sulphate  of  lead,  formed  by  the  combination  of  the 
lead  with  the  sulphuric  acid,  is  placed  under  the  lower  bracket. 

Query  —  Which  substance  does  the  acetic  acid,  in  this  ex- 
ample elect  in  preference  to  the  lead  with  which  it  was  com- 
bined ?  Ans.  —  The  zinc,  with  which  it  combines,  setting 
lead  free.  Query  —  And  which  substance  does  the  sulphuric 
acid  elect  in  preference  to  the  zinc  ?  ./7ns.  —  The  Lead,  giv- 
ing off  the  zinc  with  which  it  was  united.  Query — And 
why  is  this  action  called  double  elective  affinity  ?  Jlns.  —  Be- 
cause two  distinct  elections  took  place,  viz.  the  acetic  acid 
elects  the  zinc,  and  the  sulphuric  acid  the  lead,  for  a  new 
combination. 

This  kind  of  affinity  often  effects  the  decomposition  of 
a  substance  which  would  have  resisted  the  action  of  single 
elective  or  predisposing  affinity. 

XIX.  It  has  been  said  that  while  some  bodies  combine 
with  each  other  in  all  proportions  and  form  mixtures,  others 
have  a  limit  to  their  combination,  which  is  the  point  of 
SATURATION.  But  there  are  substances  which  combine 
with  each  other  only  in  certain  Jixed  proportions,  that  is, 


CHEMICAL    ACTION.  11 

so  many  parts  or  weights  of  one  substance,  with  a  definite 
number  of  parts  or  weights  of  another.  The  product  of 
such  a  combination  is  always  a  compound  in  which  the 
properties  of  the  constituent  parts  are  completely  neutral- 
ized. (See  XII.) 

EXAMPLE.  —  Sulphur  and  oxygen  are  apparently  heteroge- 
neous substances ;  oxygen  is  a  gas,  and  sulphur  a  solid  body. 
These  two  substances  however  unite  with  each  other  in  the 
proportion  of  16  weights  of  sulphur  with  24  weights  of  oxygen, 
in  which  case  they  form  a  compound  which  is  known  by  the 
name  of  sulphuric  acid  ;  and  whose  properties  are  totally  dif- 
ferent from  those  of  the  sulphur  or  oxygen  ;  these  are  therefore 
neutralized  by  the  combination. 

Some  bodies  combine  with  each  other  only  in  one  pro- 
portion ;  others  combine  in  two,  three,  four  and  more  fix- 
ed ratios. 

EXAMPLE. —  Zinc  and  oxygen  combine  with  each  other  only 
in  one  proportion,  forming  what  is  called  oxide  of  zinc  ;  but  the 
two  gases,  known  by  the  name  of  oxygen  and  nitrogen,  com- 
bine with  each  other  in  five  distinct  ratios,  viz. 

I   volume   of   nitrogen  with   1  volume  of  oxygen, 

1  u  it  it  it  O  tt  it  it 
j  it  tl  tl  it  3  it  ti  it 
J  tl  tt  it  it  £  ti  ti  n 

and  1         "        "  "          "      5       "        "         " 

the  five  resulting  combinations  being  two  oxides  and  three 
acids  of  nitrogen,  and  there  are  no  other  combinations  of  these 
two  substances  known. 

Similar  fixed  ratios  have  been  discovered  in  the  com- 
bination of  other  bodies  to  definite  compounds,  and  it  has 
been  observed  that  in  these  combinations  the  original  prop- 
erties of  the  ingredients  are  always  completely  neutralized, 
so  that  we  are  able  to  lay  down  the  general  principle  :  No 
two  bodies  combine  with  each  other  to  neutralization,  except 
in  ajixed  determined  proportion,  which  remains  always  the 
same,  for  the  same  two  substances. 

Now  it  has  been  remarked  and  proved  by  numerous  ex- 
periments, that  if  a  body,  A,  combines  with  another  body, 
B,  for  instance,  in  the  ratio  of  1  weight  of  A  with  2 
weights  of  B  ;  and  the  same  body  A ,  combines  with  a  third 
body,  C,  in  the  ratio,  say  of  I  weight  of  A,  to  3  of  C,  then 
the  body,  B,  will,  if  it  have  any  neutralizing  affinity  for 


12  CHEMICAL    ACTION. 

the  body  C,  combine  with  it  in  the  ratio  of  2  to  3,  or  at 
least  in  a  multiple  of  this  ratio  by  a  whole  number ;  that 
is  in  2,  3,  4,  5  or  6  times  this  ratio  ;  so  that  the  ratio  in 
which  one  and  the  same  body,  A,  combines  to  neutralization 
with  different  bodies,  B,  C,  D,  4*c,  being  once  known,  the 
neutralizing  ratio  in  which  these  bodies  combine  with  each 
other  are  also  determined  This  will  be  better  understood 
by  the  following  EXAMPLE. 

(2  Ibs.  ofB, 

Supposing  1  Ib.  of  a  substance  A.  combines  with  «(  ^  ^  ^  p' 

[  5  Ibs.  of  E; 
then  the  relation  of  the  substance,  A,  to  the  bodies,  B,  C, 

D,  E,  determines  also  that  of  the  bodies  B,  C,  D,  and   E 
to  each   other  ;    viz.  if  the  body,  B,  has   a   neutralizing 
affinity  for  C,  D,  and  E,  it  will  combine  with  them  in  the 
ratio  of 

(  with  3  Ibs.  of  C, 

2  Ibs  of  B  {  with  4  Ibs.  of  D, 

(  with  5  Ibs.  of  E. 

Further,  if  C,  has   any  neutralizing  affinity    for  C,  D, 
and  E,  it  will  combine  with  them  in  the  ratio  of 

!2  Ibs.  of  B, 
4  Ibs.  of  D, 
5  Ibs.  of  E. 

If  D  have   any  such  affinity  for  B,  C,  and  E,  it  will 
combine  with  them  in  the  ratio  of 

(  2  Ibs.  of  B, 

4  Ibs.  of  D  with  {  3  Ibs.  of  C, 

(  5  Ibs.  of  E, 

And  lastly  if  E  have  this   affinity  for   B,  C,  and  D,  it 
will  combine  with  them  in  the  ratio  of 

r  2  Ibs.  of  B, 

5  Ibs.  of  E  with    !  3  Ibs.  of  C, 

(  4  Ibs.  of  D. 

Thus  a  single  table  expressing  the  fixed  proportions  in 
which  the  body  A,  combines  respectively  with  B,  C,  D  and 

E,  has  given  us  at  once  the  fixed  proportions  in  which  B, 
C,  D,  and  E  combine  with  each  other. 


CHEMICAL    ACTION. 


13 


The  learner  will  now  be  able  to  understand  the  follow- 
ing example,  which  is  taken  from  nature  : 

We  know  from  experience  that 

37  weights  of  Muriatic  acid  combine  with  28  of  Lime, 
40     "         "  Sulphuric  acid       "         "     48  "  Potass, 
54     "         "  Nitric  acid  "         "     32  "  Soda, 

28     "         {<  Phosphoric  acid     '«         "     17  "  Ammonia. 

These  ratios  give  not  only  the  proportions  in  which  each 
of  these  substances  combines  with  that  which  is  placed  on 
the  same  line  with  it ;  but  also  the  proportion  in  which 
each  of  these  substances  combines  with  all  others.  Thus, 

28  weights  of  Lime, 

with 


37  weights  of  muri- 
atic acid  combine  to 
saturation 


40  weights  of  Sul- 
phuric acid  combine 
to  saturation 

54  weights  of  Nitric 
acid  combine  to  sat- 
uration 


with 


with 


48 
32 
17 


Potass. 


"  Soda, 

"  Ammonia, 


28  weights  of  Lime, 
48         "      "  Potass, 
32         «      "  Soda, 
17         "      "  Ammonia, 

28  weights  of  Lime, 
48         "     "    Potass, 
32         "     "    Soda, 
17         "     "    Ammonia. 


Or  we  could  also  take  any  of  the  four  substances,  Lime, 
Potass,  Soda,  or  Ammonia ;  say  soda,  and  write  the  four 
acid  substances  after  it,  viz. 

37  weights  of  Muriatic  acid, 

40         "      "  Sulphuric  acid, 

54 

28 


Nitric  acid, 
Phosphoric  acid, 


32  weights  of  / 
Soda  combine  to  /  with 
saturation  \ 

and  so  on. 

Now  as  37  weights  of  muriatic  acid  combine  in  the 
same  proportions  with  Lime,  Potass,  Soda,  and  Ammonia, 
in  which  40  weights  of  sulphuric  acid  combine  with 
these  substances,  37  weights  of  the  first  acid  are  said  to  be 
equivalent  to  40  weights  of  the  second;  and  accordingly, 
also  to  54  weights  of  Nitric,  and  to  28  weights  of  Phospho- 
ric acid.  In  like  manner  are  28  weights  of  lime  equiva- 
2 


14  CHEMICAL    ACTION. 

lent  to  48  weights  of  potass,  32  of  Soda,  17  of  ammonia. 
Or  we  may  also  say  that  37  weights  of  muriatic  acid  are 
equivalent  to  28  weights  of  lime,  48  of  potass,  32  of  soda, 
&c,  or  that  28  weights  of  lime  are  equivalent  to  37  weights 
of  muriatic,  40  of  sulphuric,  54  of  nitric,  and  28  of  phos- 
phoric acid,  and  so  on. 

We  shall  show  in  the  body  of  the  following  work  that 
similar  equivalent  numbers  have  been  found  for  a  great 
many  substances  in  the  chemical  catalogue ;  and  it  is  by 
these  numbers  that  we  are  able  to  express  the  definite  pro- 
portions in  which  one  substance  combines  tvith  all  others, 
for  which  it  has  a  strong  chemical  affinity.  —  The  smallest 
number  of  weights  of  one  substance  which  in  this  manner 
combines  with  other  substances,  is  said  to  be  a  CHEMICAL 
EQUIVALENT  for  all  other  substances  with  which  it  is  ca- 
pable of  entering  into  combination. 

Now  it  has  been  found  by  experiments  that  in  all  cases 
where  a  body  is  composed  of  two  elements,  the  sum  of 
the  equivalents  of  the  elements  is  equal  to  the  equivalent 
of  the  body  itself.  Knowing  therefore  the  equivalent  of 
the  elements  of  a  body,  we  also  know  that  of  the  com- 
pound ;  and  the  reverse,  if  the  equivalent  of  the  compound 
and  the  elements  of  its  composition  are  known,  the  equiv- 
alents of  its  elements  may  be  inferred  from  it.  This  will 
be  better  understood  from  the  following 

EXAMPLE.  —  1  weight  of  hydrogen  combines  with  about 
8  weights  of  oxygen  to  water.  Consequently  if  1  weight 
of  hydrogen  gas  is  taken  for  unity  of  comparison,  the 
equivalent  of  oxygen  will  be  8 ;  whence  that  of  water  will  be 
1  added  to  8,  equal  to  9.  And  the  reverse  ;  suppose  we 
know  that  the  chemical  equivalent,  of  water  is  9  ;  and  that 
it  is  composed  of  I  equivalent  of  water  and  1  of  oxygen. 
Knowing  the  equivalent  of  water  to  be  =  9,  we  should  at 
once  infer  that  of  the  oxygen,  which  must  be  equal  to  8. 

ANOTHER  EXAMPLE.  —  One  weight  of  hydrogen  com- 
bines with  16  weights  of  sulphur,  to  sulphuretted  hydrogen ; 
consequently  the  weight  of  hydrogen  taken  for  unity,  the 
chemical  equivalent  of  sulphur  is  16.  Now  the  chemical 
equivalent  of  oxygen  being  8,  it  is  known  that  2  equiva- 
lents of  oxygen  combine  with  1  equivalent  of  sulphur  to 


CHEMICAL    ACTION.  15 

sulphurous  acid.  Query  —  What  is  the  equivalent  num- 
ber of  sulphurous  acid  ?  Ans.  —  32.  Query  —  Why  ? 
Ans.  —  Because  it  is  composed  of  1  equivalent  of 

sulphur  =  16 
and  of  2  equivalents  of  oxygen  (each  equal  to  8)  =  16 

Consequently,  Chemical  equivalent  of  sulphurous 

acid  =  32 

Jigain  —  Supposing  we  know  the  chemical  equivalents 
of  sulphurous  acid  =  32,  and  also  that  it  is  composed  of 
1  equivalent  of  sulphur,  and  2  equivalents  of  oxygen, 
(each  equal  to  8.)  Required  the  chemical  equivalent  of 
sulphur.  Ans.  —  The  equivalent  of  sulphurous 

acid  being  =  32 
Subtract  from  it  2  equivalents  of  oxygen  (each 

equal  to  8)  =  16 

The  remainder  will  be   the  equivalent  of  sulphur  =  16. 

These  few  examples  will  be  sufficient  to  show  the  beau- 
ty and  harmony  of  the  theory  of  chemical  equivalents ; 
as  well  as  the  advantages  which  the  practical  chemist  may 
derive  from  it. 

Were  the  chemical  equivalents  of  all  bodies  unchangeable, 
and  as  correctly  determined  as  those  we  have  mentioned  in 
our  last  examples,  then  it  would  indeed  be  possible  to  intro- 
duce mathematical  precision  and  certainty  into  the  science  of 
chemistry,  which  would  then  in  no  respect  yield  to  any  of  the 
exact  sciences.  A  single  experiment  which  should  show  the 
relation  of  an  unknown  substance  to  one  with  whose  proper- 
ties we  are  already  acquainted,  would  suffice  to  determine  the 
relation  of  that  substance  to  all  other  bodies  ;  which  relation 
would,  in  most  cases,  be  found  by  a  mere  addition  or  subtrac- 
tion, as  has  been  shown  in  the  last  two  examples.  But  this  is 
far  from  being  universally  true.  The  same  limits  with  which 
the  human  understanding  invariably  meets  in  all  sciences, 
await  us  also  in  chemistry.  For  the  proportion  in  which 
bodies  combine  are  not  always  as  definitely  pronounced  as  we 
could  wish  them  to  be.  In  some  bodies  they  are  less  percep- 
tible than  in  others,  and  there  are  substances  whose  composi- 
tion is  so  vague  and  indefinite  that  thus  far,  it  has  been  impos- 
sible, even  by  the  nicest  experiments,  to  fix  upon  any  of  their 
supposed  definite  equivalents.  We  know  farther,  from  expe- 
rience, that  1  equivalent  of  one  body,  does  not  always  combine 
again  with  1  equivalent  of  another ;  on  the  contrary  it  has 


16  CHEMICAL    ACTION. 

been  found  that  1  equivalent  of  one  body  frequently  combines 
with  1,  li,  2,  3,  or  5  equivalents  of  another  ;  and  there  are  ex- 
periments and  facts,  which  have  induced  some  of  the  best 
chemists  now  living  to  suppose  that  one  equivalent  of  one  sub- 
stance may  also  combine  with  4-,  ^,  f » ;£,  ^»  and  even  £ 
equivalent  of  another  substance.  Hence  the  universal  advan- 
tage which  it  was  hoped  would  be  obtained  from  a  numerical 
computation  of  chemical  equivalents  has,  thus  far,  not  been 
realized.  For  although  we  may  be  able  to  investigate  by 
experiment  the  proportion  of  matter  or  weight  in  which  two 
substances  combine  with  each  other,  yet  will  this  investigation 
not  always  lead  us  to  a  precise  result  as  regards  the  chemical 
equivalent  of  the  compound  ;  because  we  do  not  always  know 
whether  1,  £,  2,  or  one  fourth,  one  third,  two  thirds,  one  eighth, 
or  one  sixth  equivalent  of  either  substance  is  combined  with 
one  equivalent  of  the  other.  But  as  far  as  the  whole  theory  of 
Chemical  proportions  is  supported  by  actual  experiments,  it  not 
only  serves  to  facilitate  the  labors  and  to  assist  the  memory  of 
the  practical  chemist;  but  deserves  also,  on  account  of  its 
harmony  with  other  laws  of  nature,  to  be  ranked  among  the 
most  brilliant  discoveries  of  the  human  mind. 

The  chemical  equivalents  of  a  great  number  of  substan- 
ces, as  far  as  we  have  been  able  to  determine  them  by  ac- 
tual experiments  (but  in  most  cases  unfortunately  only  by 
arithmetical  computation),  have  been  arranged  in  tables, 
of  which  one  is  attached  to  the  end  of  the  book.  From 
what  we  have  said  it  will  easily  be  seen  that  they  are  not 
in  all  cases  to  be  relied  upon  with  mathematical  certainty, 
although  many  authors  speak  of  them  as  established  facts, 
or  consider  the  whole  theory  established  beyond  any  rea- 
sonable doubt.  In  most  of  these  tables  the  weight  of  t 
equivalent  of  hydrogen  gas  is  taken  for  unity  of  compar- 
ison. The  same  is  done  in  our  table,  for  reasons  which 
we  shall  explain  hereafter  when  treating  of  hydrogen  gas. 
The  full  development  of  the  theory  of  chemical  equiva- 
lent cannot  be  given  here  (in  the  introduction  to  chemis- 
try) ;  nor  can  it  be  expected  that  the  pupil  shall  have  an 
adequate  idea  of  it  from  the  few  statements  of  facts  which 
we  have  made  in  this  section.  But  we  shall  revert  to  this 
subject  again,  and  give  a  more  complete  exposition  of  it, 
as  we  go  along,  treating  separately  of  the  most  important 
substances  of  the  chemical  catalogue. 


CHEMICAL   APPARATUS. 


17 


III.    CHEMICAL  APPARATUS. 


[It  is  to  be  understood  that  only  the  most  useful  and  essen- 
tial apparatus,  which  may  be  easily  procured,  can  find  a  place 
in  an  elementary  treatise  for  schools.  A  complete  description 
of  it  is  found  in  Berzelius's  Chemistry,  Vol.  1.] 

XX.    a.  Apparatus  for  dividing  bodies. 
Fig.  I. 


These  consist  of  mortars 
and  pestle,  (Fig.  I.) 


hammer  and  anvil,  (Fig.  II.) 


Fig.  III. 


Fig.  IV. 


knives,  (Figs.   Ill, 
IV  and  V.) 


18 


CHEMICAL    APPARATUS. 


Fig.  VI. 

Jiles,  (Fig.  VI,)  &c,  the  construc- 
tion of  which  is  sufficiently  plain  from  the  diagrams. 

b.  Apparatus  for  separating  liquids  from  solids. 
Fig.  VII. 


To  these  belong  sieves,  (Fig.  VII.) 


Fig.  VIII. 


cullenders,  (Fig  VIII.) 


Fig.  IX. 


straining  cloths,  (Fig.  IX.) 


CHEMICAL    APPARATUS. 
Fig.  X,  Fig.  XI.         Fig.  XII- 


19 


Fig.  XIII.        Fig.  XIV. 


funnels,  (Fig.  X, 
XI,  and  XII.); 
&c. 


The  decanting  jar  is  repre- 
sented in  Figs.  XIII  and  XIV. 
Its  shape  is  sufficiently  plain 
from  the  figure,  and  its  applica- 
tion in  the  pouring  of  liquids, 
easily  understood. 


Fig.  XV.         Fig.  XVI. 


Fig.  XVII. 


A  spherical  or  common  glass 
bottle,  (Figs.  XV  and  XVI,) 
with  a  small  cylindrical  tube, 
fixed  air-tight  in  the  cork, 
serves  to  separate  a  liquid  from  a 
solid  by  the  process  of  evapora- 
tion (explained  in  Natural  Phi- 
losophy). 

To  separate  a  lighter  rluid  from  a  specific 
heavier  one,  the  separatory  funnel  (Fig. 
XVII)  is  used,  which  opens  upwards  and 
downwards.  When  the  lighter  fluid  is  de- 
canted through  the  upper  aperture  the  spe- 
cific heavier  descends  through  the  lower. 


20 


CHEMICAL    APPARATUS. 
Fig.    XVIII. 


The  operations  of  the  syphon  has  already  been  described 
in  Natural  Philosophy,  Chapter  V. 

c.  Apparatus  for  the  liquefaction  of  solids. 
Fig.  XIX.  Fig.  XX. 


These  consist  of  melting 
pots,  (Fig.  XIX,)  or  cru- 
cibles, (Fig.  XX,)  made 
of  earthen  ware,  silver  or 
platinum  ; 


of  glass  vessels   called  matrasses,   of 
which  one  is  represented  in  Fig.  XXI. 


of  porcelain  saucers  and  spoons, 
(Figs.  XXII,)  for  stirring  acids 
which  would  effect  metal  or 
glass,  &c. 


Fig.  XXL 


CHEMICAL    APPARATUS. 


21 


d.  Apparatus  for  evaporation  and  crystalization. 
Both  processes  have  been  described  in  Natural  Philosophy. 
XXI.    For  this  purpose  we  make  use  of  what  are  called 


Fig.  XXIII. 


Fig.  XXIV. 


evaporating     dishes,     made    of 
porcelain,  glass,  or  silver.     (See 
Fig.  XXIII.)     Their  form  must 
be  flat,  to  present  the  greatest 
possible   surface  to    the  atmos- 
phere.     When    the   process   of 
evaporation  takes   place    under 
the  influence  of  heat  it  is 
called   a    steam-bath.      For 
this    purpose    a  flat  vessel, 
made  of  wedgewood  ware,  is 
bedded  in  hot  sand  or  ashes. 
(See  Fig.  XXIV.) 


e.  Apparatus  for  distillation. 

XXII.    This  is  a  contrivance  for  collecting  the  volatile 


Fig.  XXV. 


portion  of  a  body  which  es- 
capes through  the  process  of 
evaporation.  The  most  com- 
mon is  an  alembic,  (Fij 
XXV,)  composed  of  a  flasl 
(which  may  be  bedded  in 
sand)  the  head  of  which  fits 
air-tight  in  the  neck  of  the 
pipe,  which  is  destined  to  carry 
the  rising  gas  from  the  flask 
into  the  receiver. 


22 


CHEMICAL    APPARATUS. 
Fig.    XXVI. 


The  common  still,  (Fig.  XXVI,)  an  instrument 7 sim- 
ilar in  its  construction  to  an  alembic,  is  made  of  cop- 
per. It  is  shaped  like  a  kettle,  A,  and  has  a  hollow  mov- 
able head,  B,  to  which  a  pipe,  C,  is  attached,  leading  to  a 
spirally  formed  tube,  commonly  called  the  worm,  which 
for  the  purpose  of  cooling,  may  be  immersed  in  water. 
The  vapours  then  contained  in  it  are,  by  this  means,  con- 
densed, and  descend  in  drops  when  the  cock,  E,  is  opened. 
Fig.  XXVII. 

The"  instrument  more  gen- 
erally employed  for  distillation 
is  a  retort.  It  may  be  made 
of  glass,  porcelain,  or  metal ; 
and  is  either  as  shaped  in  Fig. 
XXVII,  or  as  represented  in 
Fig.  XXVIII.  There  is  al- 
ways a  receiver,  R,  con- 
nected with  it,  which  in 
some  instances  is  again 
provided  with  a  pipe  and 
£  stop-cock,  to  let  off  the 
distilled  liquid  at  differ- 
ent periods.  The  ope- 
ration of  this  apparatus  is  easily  understood.  When  the 
liquid  which  is  heated  in  the  retort,  A,  evaporates,  the 
volatile  parts  are  collected  by  the  receiver,  R. 


CHEMICAL    APPARATUS 


Fig.  XXIX. 


A  Florence  flask  (Fig.  XXIX,)  with 
a  pipe  fixed  air-tight  through  its  cork, 
is  a  cheap  apparatus,  answering  most 
purposes  for  which  retorts  are  used. 
The  pipe,  A,  may  be  connected  with 
a  receiver,  as  in  Figs.  XXV  [I,  and 
XXVIJI. 


f.  Apparatus  for  heating  Chemical  substances. 
X  XIII.     These    consist    in    lamps    and     furnaces. 
Fig.  XXX.  Fig.  XXXI. 


The  latter  are  either  portable  air  furnaces  with  crucible 
stands  (Figs.  XXX,  and  XXXI)  ;  or  they  are  fixed  wind- 
furnaces  of  which  one  is  represented  in  Fig.  XXXII. 
Fig.  XXXII. 


24  CHEMICAL  APPARATUS. 

Both  kinds  of  furnaces  are  so  constructed  that  the  air 
has  free  access  to  the  fire  from  below.  By  this  means  a 
continued  draught  is  created,  which,  as  we  shall  see  here- 
after, is  necessary  for  a  brisk  flame  or  free  combustion. 
For  the  heated  air  in  the  furnace  becomes  specifically 
lighter  and  escapes  through  the  upper  opening,  while  the 
outer  air  rushes  from  below  in  its  place.  (See  Natural 
Philosophy,  Chap.  V.) 
Fig.  XXXIII. 

Figs.  XXXIII,  XXXIV,  and  XXXV, 
represent  the  three  principal  kinds  of 
lamps  used  for  chemical  purposes.    Fig. 
XXXIII  represents  the  common  lamp. 
A  combustible  substance,  usually  made 
of  cotton,  called  the  wick,  is  immersed 
in  oil,  with  which  the  whole  apparatus 
is  filled,  and  is   then    lighted.      The 
flame,  nourished  by  the  oil,  which  as- 
cends through  the  wick  and  is  gradually  consumed,  throws 
out  heat  and  light  at  the  same  time. 
Fig.  XXXIV. 

Fig.  XXXIV  represents  a  spirit 
lamp.  The  main  difference  be- 
tween this  lamp  and  the  one  just 
described,  consists  in  spirit  of  wine 
being  employed  instead  of  oil,  — 
the  heat  of  the  flame  of  this  sub- 
stance being  much  more  intense 
than  that  produced  by  the  flame  of  a  common  oil  lamp. 

Fig.  XXXV. 

Fig.  XXXV  represents  an  Argand 
lamp,  with  its  stand.  This  is  as  great 
an  improvement  upon  common  lamps 
as  the  wind-furnace  upon  a  common 
fire-place.  Its  principal  advantage  over 
a  common  lamp  consists  in  a  round 
hollow  wick  through  which  the  air  is 
admitted  by  an  opening  from  below, 
causing  thereby  a  much  more  perfect 
combustion,  and  throwing  out  much 
more  light  and  heat  than  is  done  by  a  common  lamp, 


CH.EMICAL    APPARATUSj. 


25 


where  the  air  comes  only  in  contact  with  the  exterior 
part  of  the  flame.  The  flame  of  the  Argand  lamp  is 
moreover  covered  by  a  round  open  glass,  which  serves  it 
in  the  office  of  a  chimney,  through  which  the  heated  air 
ascends  and  is  replaced  by  the  air  which  enters  from  be- 
low ;  the  draft  thereby  created  tending  not  a  little  to  in- 
crease the  intensity  and  heat  of  the  flame. 
Fig.  XXXVI. 

A  convenient  contrivance 
for  heating  bodies  in  a  retort, 
is  Guiton's  Lamp-furnace. 
It  consists  of  an  iron  or  brass 
rod,  O  P,  with  several  slid- 
ing sockets,  which  serve  to 
support  the  lamp,  A,  and  the 
arms,  LF,  OG,  of  which 
there  may  be  as  many  as 
may  be  thought  expedient. 
The  arms  terminate  in  iron 
or  brass  rings  for  the  sake 
of  supporting  retorts  and 
receivers,  (see  the  figure) 
|T or  in  small  forceps  to  hold 
the  body  which  is  to  be  ex- 
posed to  the  heat  of  the 
lamp.  These  arms  may,  by 
means  of  sockets,  be  moved 
up  and  down  the  rod,  O  P,  or  turned  sideways,  and  then 
screwed  fast  to  any  particular  part  of  it,  as  the  experiment 
may  require  ;  and  the  same  may  be  done  with  the  lamp, 
in  order  to  regulate  the  heat.  The  whole  apparatus  is 
best  fastened  to  a  table,  T,  by  means  of  a  screw,  B,  in  or- 
der to  give  more  steadiness  and  security  to  the  experiment. 
Fig.  XXXVII. 

For  the  sake  of  producing  a  very  intense  heat 
with  a  common  oil  or  spirit-lamp,  an  instrument  is 
used  which  is  called  a  common  blow-pipe.  It  con- 
sists  of  a  bent  brass  tube,  whose  upper  end  is  from 
one  third  to  one  half  inch  in  diameter  ;  but  is  grad- 
ually tapering  to  a  point,  as  is  represented  in  figure 
XXXVII.  When  the  lower  (bent)  end  is  placed 
in  the  flame  of  the  lamp  and  the  upper  is  applied 


CHEMICAL    APPARATUS. 


to  the  mouth  or  nostrils,  a  stream  of  air  may  be  applied 
to  the  jet  of  the  flame  for  the  double  purpose  of  giv- 
ing it  a  horizontal  direction,  and  making  it  gradually 
taper  to  a  point,  to  which  the  body  that  is  to  be  heat- 
ed must  then  be  exposed.  The  body  must  be  placed  upon 
a  piece  of  charcoal,  which  may  be  held  by  small  forceps. 
(See  fig.  L.  page  32.) 


Fig.  XXXVIII. 


An  improvement  upon  the 
common  blow-pipe,  is  Gahn's 
blow-pipe,  (Fig.  XXXVIII.) 
which  instead  of  the  bent  tube  is 
provided  with  the  chamber  A,  to 
which  the  smaller  orificed  pipe, 
B,  is  attached.  The  advantage 
of  this  apparatus  consists  in  the 
chamber,  A,  retaining  the  mois- 
ture from  the  breath,  which, 
when  the  common  blow-pipe  is 
used,  often  stops  the  process,  or 
diminishes  the  flame. 

Fig.  XXXIX. 


A  more  convenient  contrivance  than  either  is  that  rep- 
resented in  Fig.  XXXIX.  where  the  blow  pipe  C,  commu- 
nicates with  a  bellows  A,  which  may  be  moved  with  the 
foot  by  placing  it  upon  the  board,  B,  and  by  which  means 


CHEMICAL    APPARATUS. 


27 


a  constant  stream  of  air  is  sent  through  the  jet  of  the  flame, 
D.  This  apparatus  is  particularly  used  for  closing  the 
tubes  of  barometers  and  thermometers,  and  such  similar 
purposes. 

g.  Apparatus  for  compressing  bodies,  or  extracting  liquids 

from  bodies  in  which  they  are  contained. 
Fig.  XL. 

XXIV.    For  the  purpose  of  extract- 
ing liquids  from  solids  in  which   they 
are   contained,  two  kinds  of  presses 
are  used  ;    one  with  one  screw  only, 
(Fig.  XL.)  and  the  other  with   two, 
(Fig.  XLI.)  The  press  with  one  screw 
consists  chiefly  of  an  iron  arch,  A,  fas- 
tened  to  a  block  of  wood,  B,  and  con- 
taining in  C  the  nut  through  which  the 
screw,    D,  moves  up  and  down.     The 
substances  contained  in  the  basin,  E,  are  by  this  screw 
compressed,  and  the  liquid  descends  through  the  nose,  F. 
Fig.  XLI. 


The  press  with  two  screws  (Fig.  XLI.)  consists  of  two 
boards,  A  and  B,  which  are  brought  together  by  the  two 
screws,  C,  C,  and  by  this  means  compress  the  substances 
which  are  placed  between  them.  The  remainder  of  the 
construction  is  similar  to  the  press  with  one  screw. 


28 


CHEMICAL    APPARATUS. 


Fig.  XLI1. 


When  a  solid  substance  is  to  be  dis- 
solved in  a  liquid,  an  instrument  is  often 
used,  which  is  called  the  hydrostatic,  or, 
from  its  inventor,  Count  Real's  press. 
It  consists  of  a  strong  tin  barrel,  A  B, 
which  in  C  is  provided  with  a  fine  sieve, 
and  in  D,  with  a  discharging  spout.  The 
upper  part  screws  into  a  metallic  cover 
E,  which  terminates  in  a  long  narrow 
tube,  and  is,  in  I,  provided  with  a  stop- 
cock. The  solid  substance  from  which 
an  extract  is  to  be  made,  is  first  put  in  the 
barrel  and  placed  upon  the  sieve  C  ;  on 
top  of  it  is  placed  a  tin  plate,  K,  which 
like  the  sieve,  C,  is  provided  with  a  great 
many  fine  holes  ;  the  cover  is  then  screw- 
ed upon  the  barrel,  and  the  narrow  tube, 
G  H,  filled  with  the  liquid  which  is  to 
be  employed  for  the  solution  of  the  solid. 
The  solving  power  of  the  liquid  is  pro- 
digiously increased  by  the  hydrostatic 
pressure  of  the  liquid,  (see  Natural 
Philosophy,  Chapter  VI)  which  by  this 
means  forces  its  way  through  the  solid 
substance  between  K  and  C,  and  collects 
in  the  lower  part,  B,  of  the  barrel,  whence 
it  may  be  drawn  off  by  the  discharging 
spout,  D. 


CHEMICAL    APPARATUS.  29 

Fig.  XLIII. 


The  pressure  of  liquids  is  also  taken  advantage  of  in 
the  construction  of  Brahma's  hydraulic  press.  It  consists 
of  a  large  pump  barrel,  A,  B,  C,  D,  which  communicates 
with  a  small  forcing  pump,  M  N.  The  two  pistons,  P,  P, 
work  water  tight  in  their  respective  barrels.  The  whole 
space  between  the  two  pistons  is  filled  with  water.  The 
substance  to  be  pressed  is  placed  upon  the  top,  A  B,  of 
the  large  piston,  above  which  a  strong  fixed  surface,  F  G, 
is  made  to  meet  the  pressure.  When  the  small  piston  is 
forced  down  by  means  of  the  lever,  E,  the  water  exercises 
a  pressure  upon  the  lower  end,  C  D,  of  the  large  piston, 
P,  which  will  be  as  many  times  greater  than  the  force  with 
which  the  small  piston  is  worked  down,  as  the  surface  of 
the  larger  piston  is  larger  than  the  surface  of  the  smaller 
one.  Thus,  if  the  surface  of  the  smaller  piston  be  one 
square  inch,  and  that  of  the  larger  one  square  foot,  then 
the  pressure  on  the  upper  piston  will  be  144  times  greater 
than  the  force  which  pressed  the  smaller  piston  down* 
Hence  one  man  working  on  the  lever,  E,  may  exercise 
pressure  upon  the  piston,  P,  equal  to  that  which  it  would 
take  1 44  men  of  the  same  strength  to  produce,  if  directly 
working  upon  C  D.  If  the  surface  of  the  smaller  piston 
were  only  one  fourth  of  a  square  inch,  then  the  pressure 
upon  C  D  upwards  would  be  4  times  144,  or  576  times 
greater  ;  and  so  on.  Now  it  is  easily  seen  that  the  greater 
the  power  is,  which  presses  the  piston  P,  upwards,  the 

3* 


30 


CHEMICAL    APPARATUS. 


greater  will  be  the  pressure  exercised  upon  the  body 
which  is  placed  between  the  two  surfaces,  A  B,  and  F  G  ; 
whence  the  utility  of  this  apparatus  follows  of  course. 

7i.  Apparatus  for  collecting  gases. 

XXV.    For  collecting  gases  an  apparatus    called  the 
Pneumatic  tub,  water,  or  quicksilver  bath,    is  employ- 
ed.    It  consists  of  a  tub,  A,  (see  the  figure)  in   which  a 
Fig.  XLIV. 


shelf  is  fixed  in  such  a  manner,  that  the  liquid,  common- 
ly water  or  quicksilver,  may  rise  two  or  three  inches  above 
it.  Ajar  or  receiver,  B,  filled  with  the  same  liquid  is  placed 
upon  this  shelf,  (which  for  this  purpose  must  be  provided 
with  several  holes)  with  its  mouth  downward.  The  pipe, 
C,  conducts  the  gas  which  is  forming  in  the  retort,  D,  to 
the  jar,  B,  in  which  it  rises  in  little  bubbles,  expelling 
thereby  the  liquid  of  which  it  takes  the  place. 
Fig.  XLV. 

Another  apparatus  for  collecting  gases  is 
Priestley's  bell-glass.  (Fig.  XLV.)  This 
useful  apparatus  consists  of  a  bell  glass,  A,  the 
neck,  B,  of  which  may  be  closed  or  opened 
by  means  of  the  stop-cock,  C.  This  con- 
trivance is  very  convenient  for  the  collect- 
ing of  gases,  because  in  order  to  fill  it  with 
water  or  quicksilver,  it  is  only  necessary  to 
open  the  stop-cock,  C,  and  immerse  the 
glass  perpendicularly  in  the  liquid.  As  the  glass  fills 
with  the  liquid,  the  air  escapes  through  the  neck,  B  D. 
Its  principal  use  however  consists  in  transferring  gases 


CHEMICAL    APPARATUS. 


31 


from  one  vessel  to  another ;  for  which  purpose  the  gas 
which  escapes  through  the  neck,  B  D,  need  only  be  col- 
lected by  a  receiver. 

Fig.  XLVI. 

Another  application  of  this  apparatus  is 
made  by  filling  a  bladder  (Fig.  XLVI.) 
with  a  particular  gas  that  may  be  contained 
in  the  bell-glass.  This,  as  we  shall  see 
hereafter,  is  very  desirable  for  the  sake  of 
certain  experiments.  The  bladder,  L, 
(Fig.  XLVI.)  must  for  this  purpose  be 
tied  air-tight  to  a  brass  tube,  G  H,  which 
by  means  of  the  stop-cock,  F,  may  be  clos- 
ed or  opened  at  pleasure,  and  in  G  is  made 
to  screw  to  the  extremity,  D,  of  the  neck 
of  the  bell-glass.  When  this  is  done, 
and  the  two  cocks,  G  and  F,  are  opened,  the  bell-glass 
(Fig.  XLV.)  needs  only  be  perpendicularly  immersed  in 
quicksilver  or  water,  and  the  gas  will  escape  through  the 
neck  into  the  bladder.  When  the  bladder  is  rilled,  the  stop- 
cock F,  is  closed,  and  the  barrel  G  H,  unscrewed  from 
the  bell-glass.  It  is  also  common  to  provide  the  bell,  A, 
with  a  scale  S,  (see  the  last  figure)  in  order  to  estimate 
the  volume  of  gas  which  escapes  by  the  rise  of  the  quick- 
silver or  water  in  the  bell-glass. 

i.  Apparatus  necessary  for  various  chemical  purposes. 
Fig.  XLVII. 


XXVI.     To  these   we  reckon 
stands,  (Fig.  XLVII.) 


32  CHEMICAL    APPARATUS. 

Fig.  XLVIII. 


Fig.  XLIX. 


Fig.  L. 


Fig.  LI. 


Fig.  LII. 


Fig.  LIII. 


Fig.  LIV. 


shears,  (Fig.  XLIII.) 


pincers,  (Fig.  XLIX.) 


forceps,  (Fig.  L.) 


plates,  (Fig.  LI.) 


cylindrical  glasses,  (Fig.  LII.) 


glass  tubes,  (Fig.  LIII.) 


tubs,  (Fig.  LIV.) 


UHEMI|CAL    APPARATUS. 


Fig.  LV. 


bellows,  (Fig.  LV.  ) 


and  especially  accurate  beams  and  scales  (Figs.    LVI, 
LVII,  and  LVIII.) 

The  principle  of  the  common  balance,  (Fig.  LVI1I.) 
has  already  been  described  in  Natural  Philosophy.  It 
remains  for  us  to  say  a  few  words  on  the  construction  of 
beams,  or  portable  balances  (Figs.  LVI  and  LVII.)  These 
are  insturments  of  great  utility  to  the  practical  chemist, 
and  serve  either  for  the  determination  of  the  specific  gravi- 
ty of  substances,  or  to  show  at  once  the  proportion  of  their 
chemical  compositions.  In  the  latter  case  they  are  called 
per-cent  balances.  Fig.  LVI  represents  Nicholson's  porta- 
ble balance.  It  consists  of  a  hollow  body,  «,  made  of  silver 
or  tinned  iron,  to  which  is  fastened  a  piece  of  thin  wire,  b, 
which  at  its  upper  extremity  supports  a  small  plate  or  cup, 
d.  To  the  lower  extremity  of  the  body,  a,  is  attached  an- 
other piece  of  wire,/,  stronger  than  the  one  above,  carry- 
ing a  metallic  cone,  g,  the  lower  point  of  which  is  filled  out 
with  lead  to  give  the  apparatus  a  perpendicular  direction, 


34  CHEMICAL    APPARATUS. 

when  immersed  in  water.  The  weight  of  the  whole  must 
be  less  than  the  water  which  it  displaces,  in  order  that  it 
may  swim,  (see  Natural  Philosophy,  Hydrostatics,)  and 
be  able  to  bear  a  small  additional  weight  upon  the  cup,  d, 
before  it  sinks  to  the  point,  e,  marked  upon  the  upper  wire. 
The  use  of  this  apparatus  in  determining  the  specific 
gravities  of  bodies  is  exceedingly  simple.  When  the  body 
whose  specific  gravity  is  to  be  determined  is  a  liquid,  then 
immerse  the  apparatus  first  in  water,  and  then  in  the  pro- 
posed liquid  ;  placing  in  each  case  as  many  weights  in  the 
cup,  d,  as  is  necessary  to  make  it  sink  to  the  point,  e.  The 
weight  of  the  apparatus  added  to  the  weight  placed  in  the 
cup,  d,  will  in  each  case  give  the  weight  of  equal  volumes 
of  both  liquids,  which,  divided  by  one  another,  will  give 
the  specific  gravity  of  the  liquid  in  question.  To  give  an 
EXAMPLE  :  Suppose  the  weight  of  the  apparatus  is  180 
grains,  and  the  weight  required  to  make  it  sink  in  water 
to  the  point,  e,  equal  to  42  grains  more.  Suppose  80  grains 
were  necessary  to  make  it  sink  to  the  point,  e,  in  the  oth- 
er fluid  ;  then  42  added  to  180  gives  222  grains  for  the 
weight  of  the  water ;  and  80  added  to  180  gives  260  grains 
for  the  weight  of  the  liquid ;  and  dividing  260  by  222,  we 
obtain  1, 17  for  the  specific  gravity  of  the  liquid. 

If  the  body  whose  specific  gravity  we  wish  to 
know  is  a  solid,  then  place  it  in  the  cup,  d,  and  add  to 
it  as  many  weights  as  will  sink  the  apparatus  to  the  point, 
e.  By  this  means  you  find  the  absolute  weight  of  the  body. 
For  if  the  apparatus  requires  42  grains  of  itself  to  sink  to 
the  point  e,  and  now  that  the  body  is  in  the  cup,  d,  it  re- 
quires but  30  grains,  the  body  itself  must  evidently  weigh 
12  grains.  Hence  the  absolute  weight  of  a  body  is  found 
by  subtracting  the  weights  added  to  it  when  in  the  cup,  dt 
from  the  weight  which  is  required  to  sink  the  balance  alone 
to  the  point  e.  Remove  the  body  now  from  the  cup,  d}  to  the 
hollow  cone,  g%  and  the  apparatus  will  immediately  rise ;  for 
it  will  lose  as  much  of  its  weight  as  the  water  weighs,  which 
the  body  now  displaces.  (Natural  Philosophy.)  Adding 
therefore  as  many  weights  to  the  cup,  d}  as  will  make  the 
apparatus  again  sink  to  the  point  e,  we  determine  the  abso- 
lute weight  of  an  equal  volume  of  water  ;  and  dividing  the 
absolute  weight  of  the  body  by  the  weight  of  an  equal  vol- 


CHEMICHL    APPARATUS.  35 

ume  of  water,  we  obtain  its  specific  gravity.  To  give  an 
EXAMPLE  :  Suppose  the  balance  requires  of  itself  42 
grains  to  sink  to  the  point  e,  but  when  the  body  is  in  the  cup 
it  requires  but  12  grains ;  and  if  the  body  be  now  removed 
from  the  cup,  d,  to  the  cone,  g,  5  further  grains  are  necessa- 
ry to  sink  the  apparatus  to  the  point,  e;  required  the  spe- 
cific gravity  of  the  body  1  Ans.  —  By  the  first  supposition 
it  is  evident  that  the  body  must  weigh  30  grains  ;  and  by 
the  second  it  is  plain  that  an  equal  volume  of  water  weighs 
5  grains  ;  hence  30  divided  by  5,  equal  to  6,  is  the  specific 
gravity  of  the  body.  (See  Natural  Philosophy,  Chap.  IV.) 
The  per  cent  balance  Fig.  LVII,  is  an  instrument  by 
which  the  degree  of  mixture  of  two  liquids,  or  of  a  liquid 
with  a  solid  substance  is  ascertained.  It  consists  of  a  hol- 
low body,  «,  made  of  silver  or  tinned  iron,  bearing  upon 
its  upper  extremity  a  scale,  a  b,  and  on  its  lower  end  some 
heavy  substance  to  give  the  apparatus  a  perpendicular  di- 
rection when  immersed  in  the  liquid.  The  scale  is  gen- 
erally divided  into  100  degrees,  each  degree  marking  the 
existence  of  1  portion  of  one  liquid  in  another,  or  of  a  solid 
substance  in  a  liquid.  But  such  a  scale  will  only  serve  for 
one  particular  kind  of  mixture,  and  must  be  altered  or 
changed  if  applied  to  another.  Such  are  the  beer,  bran- 
dy or  spirit  scales,  which  by  the  degree  of  their  immersion 
in  these  respective  liquids,  show  the  quantity  of  alcohol 
contained  in  them.  The  deeper  they  immerse,  the  less 
water,  and  consequently  the  more  alcohol  is  contained  in 
these  liquids  ;  alcohol  being  specifically  lighter  than  water. 
(See  Natural  Philosophy,  Chap.  IV.)  But  the  scale  used 
for  brandy  would  not  answer  for  beer  or  wine,  and  vice 
versa. 

Tc.  Lutes. 

XXVII.  These  are  employed  to  join  together  the  parts 
of  vessels  which  are  used  in  distillation,  to  prevent  the  es- 
cape of  vapors.  A  mixture  of  China  clay  with  a  solu- 
tion of  borax  will  do  for  metallic  vessels.  When  the  liquid 
which  is  to  be  distilled  is  not  corrosive,  slips  of  bladder  or 
paper  spread  with  gum  arabic  or  flour-paste  will  answer 
the  purpose;  8  parts  of  yellow  wax  mixed  with  one  part 
of  turpentine  oil,  forms  a  very  good  resinous  lute. 


36  CHEMICAL    COMPOSITION   OF   BODIES. 


TV.     CHEMICAL  COMPOSITION  OF  BODIES. 

XXVIII.  All  bodies  in  nature  are  either  animate  or  in- 
animate.    The  former,  to  which  belong  the  plants  and  an- 
imals, are  composed  of  a  variety  of  exceedingly  delicate 
vessels,  filled  with  liquids,  of  which  each  has  a  particular 
office,  and  the  assemblage  of  which  forms  what  is  called 
their  organization.     Hence   it  is  also  customary  to  call 
plants  and  animals  organized  or  organic  bodies,  in  opposi- 
tion to  dead  or  inanimate  substances,  which  being  merely 
composed  of  particles  kept  together  by  the  power  of  cohe- 
sion, are  said  to  be  unorganized  or  inorganic. 

XXIX.  With  regard  to  chemistry,  all  unorganized  or 
inorganic  bodies  are, 

I.  Either  simple  or  compound  ;  that  is,  either  as  yet 
not  known  to  contain  other  ingredients,  or  composed  of 
two  or  more  heterogeneous  substances. 

2-  The  compounds  of  unorganized  bodies  are  most  al- 
ways formed  by  a  binary  combination  (combinations  of  two 
and  two  substances).  Thus  water  is  composed  of  two  el- 
ements, oxygen  and  hydrogen  ;  Saltpetre  of  two  substan- 
ces, nitric  acid  and  alkali,  of  which  each  is  again  a  com- 
pound of  two  other  substances  :  (nitric  acid  is  a  compound 
of  nitrogen  and  oxygen,  and  alkali  a  compound  of  Potas- 
sium and  oxygen.)  See  introduction,  VII. 

3.  The  compounds  of  unorganized  bodies  can,  in  most 
cases,  be  produced  by  the  combination  of  their  elements. 
Thus,  water  may  be  produced,  as  we  shall  see  hereafter, 
by  combining  oxygen  and  hydrogen  in  the  proper  propor- 
tions; saltpetre  may  be  produced  by  a  combination  of 
nitric  acid  and  alkali,  &c. 

Organized  bodies,  on  the  contrary,  are 

1.  Generally  composed  of  more  than  two  elements. 

2.  They  cannot  be  produced  by  art,  through   a  combi- 
nation of  their  chemical  ingredients  ;  because  they  all  con- 
tain a  certain  vivifying  principle,  totally  unknown  to  us  ; 
and  which  will  probably  forever  escape  all  our  anatomical 
and  chemical  researches. 

XXX.  A  vast  number  of  organized    and  unorgan- 


CHEMICAL    COMPOSITION    OF    BODIES. 


37 


ized  bodies  have  been  subjected  to  chemical  analysis,  and, 
by  means  of  art,  been  decomposed  into  their  ingredients  ; 
but  there  are  fiftyfour  substances,  which,  thus  far,  have 
resisted  all  attempts  to  decompose  them,  and,  on  that 
account,  are  called  elements.  Of  these,  4  are  gaseous  or 
aeriform  bodies  ;  9  are  solid,  non-metallic  substances  ; 
and  41  are  metals.  We  shall  here  annex  their  names, 
and  propose  to  treat  separately  of  the  properties  and  com- 
binations of  each  in  the  course  of  this  book. 

NOMENCLATURE    OF    ELEMENTS. 

a.  Gaseous  Elements. 

1.  Oxygen,  3.  Nitrogen, 

2.  Hydrogen,  4.  Chlorine. 

b.  Solid  Substances. 


5.  Carbon, 

10.  Iodine, 

6.  Sulphur, 

1L  Bromine, 

7.  Selenium, 

12.  Silicon, 

8.  Phosphorus, 

13.  Fluorine. 

9.  Boron, 

c.  Metals. 

14.  Potassium, 

32.  Iridium, 

15.  Sodium, 

33.  Osmium, 

16.  Lithium, 

34.  Nickel, 

17.  Calcium, 

35.  Iron, 

18.  Barium, 

36.  Lead, 

19.  Strontium, 

37.  Tin, 

20.  Magnesium, 

38.  Copper, 

21.  Glacinum,or  Berillium,  39.  Zinc, 

22.  Yttrium, 

40.  Bismuth, 

23.  Allumium, 

"41.  Cobalt, 

24.  Zirconium, 

42.   Antimony, 

25.  Thorium, 

43.  Arsenic, 

26.  Mercury, 

44.  Manganese, 

27.  Silver, 

45.  Tellurium, 

28.  Gold, 

46.  Titanium, 

29.  Platinum, 

47.  Cerium, 

30.   Palladium, 

48.  Uranium, 

31.  Rhodium, 

49.  Columbium, 

4 

38  CHEMICAL    COMPOSITION    OF    BODIES. 

50.  Tungsten,  (Wolfram,)     53.  Molybdenum, 

51.  Cadmium,  54.  Vanadium. 

52.  Chromium, 

And  of  these  54  elements  the  whole  infinite  variety  of 
bodies  is  composed  ! ! 

XXXI.  The  various  chemical  compositions  arising  from 
the  combination  of  these  elements  may  again  be  arranged 
under  six  different  heads  : 

1.  Oxides.     This  name  is  applied  to  all  combinations 
of  oxygen  with  another  element.     Thus,  the  combination 
of  oxygen  with  iron  is  called  oxide  of  iron  ;  that  of  oxygen 
with  manganese,  oxide  of  manganese,  &c. 

2.  Adds.     These  are  combinations  of  certain  substan- 
ces with  acidifying  (acid-producing)  principles,  common- 
ly oxygen  or  hydrogen,  and  distinguish  themselves  by  the 
following  properties  : 

a.  They  have  generally  (not  always)  a  sour  taste. 

b.  Most  of  them  are  soluble  in  water  ;  and  change  blue 
vegetable  colors  into  red. 

c.  They  are  all  negatively  electric;  (Natural  Philoso- 
phy, Chap.  IX.)  that  zs,  they  adhere  to  the  positive  or  zinc 
pole  of  the  voltaic  pile.     (To  understand  this  more  com- 
pletely see  the  remark  on  the  following  page.) 

d.  Combined  with  solid   substances  they  form  salts,  or 
at  least  substances  which  bear  a  great  resemblance  to  salts. 
The  last  mentioned  properties  are,  by  modern  chemists, 
considered  the  most  characterizing  and  essential  qualities 
of  acids. 

3.  Bases.     To  this  class  belong  all  substances  remark- 
able for  the  following  two  properties  : 

a.  When  combined  with  acids  they  form  salts  ;  and 

b.  When  separated  from  a  combination  with  an  acid  by 
the  action  of  a  voltaic  battery,  they  adhere  to  the  negative 
pole.      They  are  consequently  positively  electric. 

*  Not  all  acids  have  a  sour  taste  ;  neither  do  all  acids  necessarily 
contain  oxygen,  as  it  was  once  believed.  Prussic  acid,  for  instance, 
has  a  bitter  taste,  and  contains  no  oxygen  in  its  composition. 


CHEMICAL    COMPOSITION    OF    BODIES  39 

The  learner  ought  to  direct  his  attention  particularly  to  the 
distinguishing  characteristic  between  acids  and  salts ;  viz. 
that  the  acids  are  negatively,  and  the  bases  positively  electric. 

4.  Salts.     So  are  termed  the  almost  innumerable  com- 
binations of  the  bases  with  the  acids. 

5.  Sulphides  and  Chlorides.     These  are  combinations 
of  sulphur  or  chlorine  with  an  element,  commonly  a  metal. 

6.  Alloys  of  Metals.     These  are  combinations  of  one 
metal   with    another.     The  combinations  of  quicksilver 
with  other  metals  have  received  the  special  name  of  Amal- 
gams. 

The  theory  of  Galvanic  electricity,  as  well  as  that  of  the 
voltaic  pile  or  battery,  has  already  been  given  in  the  ninth 
chapter  of  Natural  Philosophy.  It  has  there  been  stated,  that 
the  most  important  experiments  which  can  be  made  with  the 
galvanic  battery  belong  to  chemistry.  This  is  so  far  true  that 
it  may  well  be  said  that  the  theory  of  Galvanic  electricity  has 
changed  the  face  of  the  science  of  Chemistry.  Its  influence 
upon  the  chemical  decomposition  of  bodies  stands  unrivalled 
by  any  other  agent  in  nature,  and  is  truly  universal.  There  is 
hardly  a  substance  in  nature,  upon  which  galvanic  electricity 
does  not  more  or  less  exercise  its  influence  ;  and  by  its  agency 
the  most  difficult  chemical  decompositions  have  been  effected 
with  comparative  ease  and  facility. 

EXAMPLE.  —  The  fixed  alkalies,  a  class  of  bodies  with  whose 
properties  we  shall  become  acquainted  in  the  3d  chapter,  were 
believed  to  be  elements,  and  resisted  every  attempt  to  decom- 
pose thenr,  until  the  brilliant  discoveries  of  Davy  and  Berze- 
lius,  who  dissolved  them  into  their  elements  by  means  of  pow- 
erful Galvanic  Batteries.  Nor  is  this  decomposing  power  of 
Galvanic  electricity  confined  to  a  few  chemical  compounds ; 
for  nearly  all  the  acids,  and  the  class  of  bodies  we  have  dis- 
tinguished by  the  name  of  salts,  yield  their  elements  when  ex- 
posed to  the  action  of  this  universal  agent.  It  is  on  this  ac- 
count, Galvanic  Electricity  has  become  a  criterion  (and  indeed, 
as  we  have  said  before,  the  best  criterion  we  have)  of  the 
basic  or  acid  nature  of  a  chemical  substance.  For  whenever 
a  salt  is  decomposed  into  its  two  principal  constituents,  the 
acid  and  the  basis,  the  acid  adheres  invariably  to  the  positive, 
and  the  basis  to  the  negative  pole  of  the  galvanic  battery.  Now 
as  the  positive  or  zinc  pole  of  the  battery  attracts  only  nega- 
tive electric  bodies,  (see  Natural  Philosophy,  Chap.  IX.)  and 
the  negative  or  copper  pole  attracts  positively  electric  sub- 


40 


CHEMICAL    COMPOSITION    OF    BODIES. 


stances,  we  conclude  that  all  acids  are  in  reference  to  the 
class  of  bodies  which  are  called  bases,  negatively,  and  all 
bases  in  reference  to  the  acids,  positively  electric  substances. 
But  it  does  not  follow  from  this  that  a  basis  cannot  of  itself  be 
attracted  by  either  of  the  two  poles,  or  that  an  acid  cannot  be 
composed  of  two  elements,  which  evince  again  opposite  elec- 
tricities to  each  other.  This  as  we  shall  soon  see,  occurs 
frequently  enough  ;  but  it  is  sufficient  for  us  at  present,  to 
understand  the  difference  between  an  acid  and  a  basis,  as  we 
shall  revert  to  this  subject  again  in  the  fourth  Chapter. 

We  shall  now  describe  the  manner  in  which  the  combina- 
tions of  the  almost  innumerable  class  of  bodies   which   are 
characterized  by  the  names   of  salts  and  acids,  is  effected  by 
galvanic  electricity.     (See  Natural  Philosophy,  Chapter  IX.) 
Fig.  LIX. 


If  the  trough  apparatus  (Fig.  LIX.)  is  used,  then  the  cells, 
A,  are  filled  with  water,  which  contains  in  solution  a  quan- 
tity of  common  salt,  or  which  is  mixed  with  a  small  portion 
of  muriatic  or  sulphuric  acid.  The  plates,  B,  which  are  fit- 
ted to  these  cells  and  connected  by  a  slip  of  wood,  are  then 
let  down  into  the  cells,  and  the  two  conducting  wires,  Z 
and  C,  (of  which  Z  is  connected  with  the  positive,  or  zinc 
pole,  and  C  with  the  negative  or  copper  pole)  are  brought 
in  contact  with  the  substance,  S,  which  is  to  be  submitted  to 
the  agency  of  the  battery.  Now  if  this  happens  to  be  a  salt, 
it  has  been  found  that  the  acid  of  which  it  is  composed  ad- 


CHEMICAL    COMPOSITION    OP    BODIES.  41 

heres  invariably  to  the  positive  or  zinc  pole,  Z,  and  the  basis 
to  the  negative,  or  copper  pole,  C,  of  the  battery. 

A  very  convenient  apparatus  of  this  kind,  which  may  be  at 
pleasure  increased  or  diminished,  is  Count  Stadion's  Couronne 
Fig.  LX. 


des  Tasses,  or  cup-battery.  It  consists  of  a  number  of  cups 
of  glass  or  wedgewood,  (see  Fig.  LX.)  In  each  cup  is  placed 
a  plate  of  zinc,  and  another  of  copper,  in  such  a  manner  that 
the  metals  do  not  touch  each  other  in  the  cups ;  but  are  without 
connected  with  each  other  by  slips  of  metal.  The  same  order 
of  plates  zinc,  copper,  zinc,  copper,  &c,  is  of  course  preserved 
throughout  the  apparatus.  When  the  cups  are  filled  with  a 
solution  of  salt  or  muriatic  acid,  then  the  effect  is  the  same  as 
that  produced  by  the  trough-battery.  It  is  easily  perceived 
that  the  strength  of  such  an  apparatus  may  be  increased  or  di- 
minished by  employing  a  greater  or  smaller  number  of  cups. 

To  account  for  the  chemical  decomposition  of  bodies 
by  Galvanic  Electricity,  several  ingenious  theories  have 
been  invented,  among  which  that  of  Sir  Humphrey  Davy 
deserves  decidedly  the  preference.  He  supposes  the  ele- 
ments of  all  chemical  compounds  to  be  originally  possess- 
ed of  opposite  electricities.  These  opposite  electricities 
are,  by  the  chemical  affinity  which  these  elements  have  for 
one  another,  kept  in  a  perfect  state  of  equilibrium.  But 
when  such  a  compound  is  exposed  to  the  agency  of  a  gal- 
vanic battery,  then  the  attractive  and  repulsive  force  of  the 
two  opposite  poles,  effect  a  separation  of  its  elements  ;  the 
negatively  electric  element  flies  to  the  positive  or  zinc  pole, 
and  the  positively  electric  ingredient,  to  the  negative  pole 
of  the  battery.  Those  substances  which  adhere  to  the  neg- 
ative pole  are  then  said  to  be  positively  electric ;  and 
those  which  adhere  to  the  positive  pole  of  the  battery  are 
called  negatively  electric  bodies.  Thus  according  to  what 
4* 


42  RECAPITULATION. 

we  have  said  all  acids  are,  in  reference  to  those  substances 
which  we  call  bases,  negatively  electric  ;  and  all  bases 
are,  in  reference  to  the  acids,  positively  electric  substances. 
This  theory,  although  there  are  several  objections  to  it, 
is  strongly  corroborated  by  some  very  prominent  phenom- 
ena, which  accompany  the  decomposition  of  salts  by  gal- 
vanic Electricity  ;  and  of  which  we  shall  have  an  oppor- 
tunity to  speak  hereafter  when  treating  of  salts. 


RECAPITULATION. 

[The  preceding  Introduction,  contains  the  outlines  of  Gene- 
ral Chemistry.  It  will  therefore  be  well  for  the  teacher  to  go 
over  it  a  number  of  times —  until  he  is  perfectly  satisfied  that 
his  pupils  have  understood  the  definition  of  chemistry,  andean 
give  a  tolerably  good  account  of  the  laws  of  affinity  and  chem- 
ical action.  Not  until  then  ought  they  to  commence  the  study 
of  the  first  chapter.] 

I.     QUESTIONS  ON  DEFINITIONS. 

[I.]  Into  how  many  classes  are  all  natural  sciences  di- 
vided 1  What  are  these  ? 

[II.]  What  is  the  object  of  Natural  History  1  Which 
are  the  three  great  branches  of  Natural  History  1 

[III.]  What  is  the  object  of  Natural  Philosophy  ?  Into 
what  two  branches  has  Natural  Philosophy  been  divided  ? 
How  do  you  define  Chemistry  1 

[IV.]  What  do  you  call  the  peculiar  kind  of  attraction 
which  is  only  manifest  in  contact,  and  which  is  the  cause 
of  a  change  in  the  properties  of  bodies  ? 

Give  an  example. 

[V.]  In  how  many  different  ways  does  the  chemical 
affinity  which  one  body  has  for  another  manifest  itself  ? 
What  are  these  two  ways  1  What  is  the  first  of  these 
processes  called  1  What  the  second  ? 

Give  an  example  of  chemical  composition  or  synthesis. 
Give  an  example  of  chemical  analysis. 


RECAPITULATION.  43 

What  is  the  difference  between  mechanical  and  chemical 
separation  ?  Give  instances  of  mechanical  and  chemical  di- 
vision. 

[VF.]  What  are  the  parts  obtained  by  a  chemical  sep- 
aration or  analysis  called?  What  is  the  body  called  from 
which  they  are  derived  ? 

Give  an  example. 

[VII.]  When  do  you  call  a  body  composed  of  nearer 
and  more  remote  ingredients  1 

Give  an  example. 

Which,  in  your  example  are  the  nearer,  and  which  the 
more  remote  ingredients  ? 

[VIII.]  What  are  those  substances  called  which  are 
not,  as  yet,  decomposed  by  any  means  in  our  power  1  Does 
it  follow  from  this  that  all  substances  which  are  now  con- 
sidered as  elements  are  really  incapable  of  analysis  ? 

What  then  does  the  word  element  express  in  chemistry  ? 

II.     QUESTIONS  ON  CHEMICAL  ACTION. 

[IX.]  What  kind  of  attraction  must  be  considered  as 
the  principal  cause  of  all  chemical  phenomena?  What 
changes  does  chemical  affinity  produce  on  bodies  which 
are  subjected  to  its  action  ? 

[In  the  answerto  this  question  the  pupil  ought  only  to  enu- 
merate the  three  principal  changes,  a,  &,  c,  printed  in  italics.] 

Give  examples  of  changes  produced  in  the  temperature  ; 
of  changes  produced  in  the  physical  properties  of  bodies  ; 
and  of  changes  produced  in  aggregate  form  of  bodies. 

[X.]  Does  chemical  action  ever  take  place  without  a 
change  of  temperature  ?  What  important  fact  do  you 
know  respecting  it  ?  Does  heat  generally  favor  or  coun- 
teract chemical  affinity  1 

Give  examples. 

[XI.]  What  is  the  greatest  obstacle  to  chemical  affin- 
ity 1  Why  do  bodies  combine  readiest  with  each  other, 
when  one  or  the  other  has  been  reduced  to  the  fluid  state  ? 
Why  does  heat  increase  the  action  of  chemical  affinity? 


44  RECAPITULATION. 

What  general  inference  has  been  drawn  from  this  ?     Is 
this  rule  without  exception  ? 

What  would  take  place  if  there  were  no  cohesive  attraction 
to  counteract  the  chemical  affinities  of  bodies  ?  How  must 
chemical  affinity  and  cohesive  attraction  be  considered  in  ref- 
erence to  each  other? 

[XII.]    When  are  two  bodies  said  to  be  neutralized  ? 

Give  examples  of  neutralization. 

In  what  state  are  potash  and  sulphuric  acid  contained  in  the 
salt  which  is  formed  by  their  combination  ?  What  is  neces- 
sary in  order  to  effect  a  complete  neutralization  ? 

[XIII.]  What  are  those  combinations  called,  in  which 
the  ingredients  still  preserve  a  portion  of  their  original 
properties  ? 

Give  an  example  of  such  a  combination. 

[XIV.]  To  what  must  we  have  recourse  in  order  to 
decompose  a  chemical  compound  into  its  constituent  parts  ? 
What  is  that  kind  of  chemical  attraction  called,  in  con- 
sequence of  which  a  body  quits  a  combination  already  ex- 
isting, for  the  sake  of  forming  a  new  one  ?  Why  is  this 
attraction  called  elective  affinity  1 

Give  an  example  of  the  action  of  elective  affinity.  (Ex- 
plain the  figure,  page  7.) 

What  substance,  in  your  example,  shows  an  elective  affinity 
for  potash  ?  Why  ? 

[XV.]  What  is  the  product  of  the  combination  of  a  solid 
body  with  a  flujd  called  ?  Does  the  affinity  between  a  solid 
and  a  liquid  substance  continue  forever,  or  is  it  limited  to 
a  certain  point?  How  is  that  point  called,  beyond  which 
the  solving  power  of  the  liquid  ceases  to  operate  upon  the 
solid  1  What  is  the  solution  itself  said  to  be,  when  arrived 
at  this  point  1 

Give  an  example. 

[XVI.]  Upon  what  three  things  does  the  saturation  of 
liquids  principally  depend  ?  Is  there  no  exception  to  the 
general  rule,  that  heat  increases  the  solving  power  of 
liquids'? 

Give  examples. 


RECAPITULATION.  45 

[XVII.]  What  do  some  compounds  of  two  substances 
require  for  their  decomposition  ?  When  is  this  the  case  1 
What  do  you  call  this  kind  of  affinity  1 

Give  an  example.     (Explain  the  table  on  page  9.) 

To  what  do  some  philosophers  ascribe  these  phenomena  ? 
Why? 

What  substance  in  your  example  (page  9)  exercises  a  pre- 
disposing affinity  upon  oxygen  ?  Why  ?  By  what  means 
does  the  acid  predispose  the  oxygen  for  a  combination  with 
the  zinc  ? 

[XVIII.]     What   does  frequently   happen    when   two 
compounds   are    brought  together  in   a  state  of  solution  ? 
What  is  this  compound  action  said  to  be  caused  by  ? 
Give  an  example.     (Explain  the  table  on  page  10.) 
Which  substance,  in  your  example,  does  the  acetic  acid 
elect  in  preference  to  the  lead,  with  which  it  was  combined  ? 
Which  substance  does  the  sulphuric  acid  elect  in  preference 
to  the  zinc  ?     And  why  is  this  action  called  double  elective 
affinity  ? 

[XIX.]  In  what  other  manner  do  bodies  combine,  be- 
sides forming  mixtures,  or  dissolving  others  to  saturation  ? 
What  sort  of  compound  do  we  always  obtain  from  a  com- 
bination in  fixed  proportions  ? 

Give  an  example. 

Do  bodies  always  combine  with  each  other  in  only  one 
fixed  proportion  1  Give  an  example  where  one  substance 
combines  .with  another  in  several  fixed  proportions  ? 

Have  similar  fixed  substances  been  discovered  in  the 
combinations  of  other  bodies  ?  And  what  has  been  ob- 
served in  reference  to  these  combinations  1  What  general 
principle  are  we  enabled  to  lay  down,  from  these  observa- 
tions ? 

If  the  remainder  of  this  section  should  be  found  too  diffi- 
cult for  the  beginner,  it  may  be  omitted  until  reviewing  the 
first  four  chapters  of  the  book.  But  it  would  be  better  for 
him  if  he  could  explain  the  example  on  page  12.  If  he  has 
understood  it  well,  let  him  take  the  substance  B,  in  reference 
to  A,  C,  D,  E,  and  F.  and  determine  from  that  the  relation  of 
A  to  C,  to  D,  E,  and  F,  &c.  The  better  he  understands  this 
example,  the  better  will  he  be  able  to  comprehend  the  one 
which  is  taken  from  nature,  and  which  consists  of  larger  pro- 
portions. 


46  RECAPITULATION. 

Let  the  pupils  now  explain  the  table  on  page  13.  —  The 
teacher  may  also  let  them  copy  that  table,  and  then  ask  the 
following  questions  :  Ques.  —  Why  are  37  weights  of  mu- 
riatic acid  said  to  be  an  equivalent  to  40  weights  of  sulphuric 
acid  ?  Why  are  40  weights  of  sulphuric  acid  an  equivalent  to 
54  of  nitric  acid,  or  to  28  of  phosphoric  acid  ?  Why  are  28 
weights  of  lime  equivalent  to  48  weights  of  Potass,  or  to  32 
of  soda  ? 

What  is  the  smallest  number  of  weights  of  one  sub- 
stance called  which  combines  to  saturation  with  all  other 
substances  for  which  it  has  a  strong  chemical  affinity  ? 
By  what  means  is  the  chemical  equivalent  of  a  compound 
substance  found,  when  the  chemical  equivalents  of  its 
elements  are  known  1 

Explain  example  I.  Explain  example  II.  Explain 
example  III. 

III.     QUESTIONS  ON  CHEMICAL  APPARATUS. 

[XX. J  a.  What  instruments  are  principally  used  for 
dividing  bodies  ? 

b.  What   instruments  are  used  for  separating  liquids 
from  solids.     Explain  the  separatory  funnel,  (Fig.  XVII, 
page  19)  and  its  operation. 

c.  What  apparatus  is  used  for  the  liquefaction  of  solids. 

[XXI  ]  d.  What  apparatus  is  used  for  evaporation  and 
crystallization  1  Why  must  the  form  of  evaporating  dish- 
es be  flat  1  What  is  the  process  of  evaporation  called, 
when  it  takes  place  under  the  influence  of  heat  1  What 
apparatus  is  used  for  this  purpose  1 

[XXII.]  e.  What  is  the  most  common  apparatus  used 
for  collecting  the  volatile  portion  of  a  body  which  escapes 
through  the  process  of  evaporation  ?  Describe  Fig.  XXV. 
Describe  the  common  still,  (Fig.  XXVI.)  What  is  the 
name  of  the  instrument  most  commonly  employed  in  distil- 
lation ?  Explain  Figs.  XX VII  and  XXVIII.  What  other 
apparatus  answers  most  purposes  for  which  retorts  are  used  ? 

f.  In  what  consists  the  apparatus  for  heating  chemical 
substances  1  On  what  principle  are  both,  the  portable  air- 


RECAPITULATION.  47 

furnace  with  crucible  stands,  and  the  fixed  wind-furnace 
constructed  ?  What  is  the  construction  of  the  common 
lamp?  What  is  the  difference  between  a  common  lamp 
and  a  spirit  lamp  1  In  what  consists  the  principal  advan- 
tage of  an  Argand's  lamp  over  a  common  lamp  ?  For 
what  purpose  is  the  flame  of  an  Argand's  lamp  covered 
with  a  cylindrical  open  glass  ? 

How  is  Guiton's  lamp  furnace  constructed  1  (Explain 
Fig.  XXXVI,  page  25.) 

What  is  the  name  of  the  instrument  which  is  used  for 
producing  a  very  intense  heat  with  a  common  oil  or  spirit 
lamp?  Of  what  does  it  consist?  Explain  its  operation 
and  the  manner  in  which  it  is  used. 

What  is  the  difference  between  Gahn's  blow-pipe  and 
the  common  blow-pipe  ?  Explain  Fig.  XXXVIII.  In 
what  does  the  advantage  of  this  apparatus  consist? 

What  other  still  more  convenient  contrivance  is  there, 
than  either  the  common  or  Gahn's  blow-pipe.  Explain 
Fig.  XXXIX. 

[XXIII. ]  How  many  different  kinds  of  presses  are 
used  for  extracting  liquids  from  solid  substances.  Explain 
Fig.  XL.  Explain  Fig.  XLI. 

What  apparatus  is  frequently  used  when  a  solid  sub- 
stance is  to  be  dissolved  in  a  liquid  ?  Describe  Fig. 
XLII. 

How  is  Brahma's  Hydraulic  press  constructed  ?  Ex- 
plain Fig.  XL1II. 

[XXIV.]  What  apparatus  is  used  for  collecting  gases  ? 
Describe  Fig.  XLIV.  What  other  apparatus  is  used  for 
collecting  gases?  Explain  Fig.  XLV.  What  applica- 
tion is  made  of  Priestley's  bell  glass  ?  Explain  Fig. 
XLVI. 

[XXV.]  What  other  apparatus  is  used  for  various  other 
chemical  purposes  ?  Explain  Nicholson's  portable  balance 
Fig  LVII.  How  is  the  specific  gravity  of  a  liquid  deter- 
mined by  means  of  Nicholson's  portable  balance?  (Ex- 
plain the  example,  page  34.)  How  is  Nicholson's  balance 
to  be  used  when  the  body  whose  specific  gravity  we  wish  to 
determine  is  a  solid  ?  (Explain  the  example  on  page  35.) 


48  RECAPITULATION. 

What  sort  of  an  instrument  is  the  per-cent  balance  ? 
How  is  it  constructed  1  (explain  Fig.  LVII.)  Can  the 
scale  which  is  used  for  one  mixture  of  liquids  be  employ- 
ed also  for  another  ? 

[XXVI.]  For  what  purpose  are  lutes  employed  ? 
What  kind  of  lute  will  answer  for  metallic  vessels  ?  What 
sort  of  lute  will  answer  for  liquids  which  are  not  corrosive  ? 
What  composition  makes  a  good  resinous  lute  ? 

IV.     QUESTIONS  ON  THE    CHEMICAL  COMPOSITION    OF 
BODIES. 

[XXVII.]  To  what  class  of  bodies  belong  plants  and 
animals  ?  Of  what  are  plants  and  animals  composed  ? 
What  are  all  inanimate  substances  merely  composed  of? 

[XXVIII.]  What  characterizing  properties  have  all 
inanimate  bodies  in  reference  to  chemistry  1  (The  answer 
to  this  question  consists  in  the  recitation  of  the  three  heads, 
1,  2,  3,  printed  in  italics.)  Give  an  example  of  binary 
combinations  of  bodies.  What  characteristics,  on  the 
contrary,  distinguish  all  organized  bodies  ?  How  many 
different  substances  are  there,  which  have  thus  far  resisted 
all  attempts  to  decompose  them  ?  What  are  they  there- 
fore called  ?  How  many  of  these  elements  are  gaseous  ? 
How  many  are  non-metallic  solid  substances  ?  How  many 
are  metals  1 

If  the  teacher  thinks  fit,  the  pupils  might  now  commit  their 
namevS  to  memory,  or  they  may  also  omit  this,  until  the  review- 
ing of  the  book. 

[XXIX.]  Under  how  many  different  heads  may  the  va- 
rious chemical  compositions,  arising  from  the  combination 
of  these  elements  be  arranged  1  What  are  they  ?  (The 
answer  to  this  question  consists  in  the  enumeration  of  the 
six  heads,  Oxides,  Acids,  Bases,  &>c. 

What  substances  are  called  oxides? 

Give  examples. 

What  substances  are  called  acids  ?  What  are  the  char- 
acterizing properties  of  the  Acids  ? 

By  what  properties  are  those  bodies  distinguished  which 
are  called  Bases  1 


RECAPITULATION.  49 

What  are  salts? 

What  are  sulphides  and  chlorides  ? 

What  do  you  understand  by  alloys  of  metals  I 

[Upon  the  remainder  of  this  section  the  teacher  need 
ask  but  a  few  questions,  as  the  same  subject  occurs  again 
in  the  4th  chapter.] 

What  becomes  of  all  salts  when  exposed  to  the  action 
of  Galvanic  Electricity  ?  Why  is  galvanic  electricity  the 
best  criterion  of  a  salt  or  an  acid  1  Describe  the  manner 
in  which  salts  are  decomposed  by  galvanic  electricity  ? 
(Explain  Fig.  LIX.) 

Of  what  does  Count  Stadion's  Cup-battery  (Couronne 
des  Tasses)  consist?  (Explain  Fig.  LX.) 

What  is  Sir  Humphrey  Davy's  theory  with  regard  to  the 
electrical  phenomena  exhibited  by  all  chemical  coin- 
pounds?  What,  according  to  this  theory,  are  all  those 
substances  called  which  adhere  to  the  negative  pole  of  the 
galvanic  pile  ?  What,  those  which  adhere  to  the  positive 
pole? 

What  are  all  acids  in  reference  to  that  class  of  bodies, 
which  are  called  bases  ?  What,  all  bases  with  regard  to 
those  substances  called  acids  ? 


CHAPTER   I. 


OP  THE   PROPERTIES   AND   COMBINATIONS    OF  THE   FOUR 

GASEOUS   ELEMENTS,  OXYGEN,  HYDROGEN, 

NITROGEN,  AND  CHLORINE. 

A.    Oxygen* 

§  1.  Properties  of  oxygen.  By  the  name  of  oxygen 
we  distinguish  a  gas  contained  in  our  atmosphere,  of  which 
it  constitutes  about  21  per  cent ;  (being  the  T2^  part  of 
the  whole  atmosphere).  It  is  also  a  component  part  of 
water,  forming  nearly  T80^j  of  its  whole  weight.  It  is 
colorless,  a  litile  heavier  than  atmospheric  air,  and  insol- 
uble in  water,  and  is  destitute  of  either  smell  or  taste. 
Its  presence  is  absolutely  necessary  to  the  continuance  of 
animal  life  ;  but  breathed  in  its  pure  state  it  is  injurious, 
because  it  affects  the  lungs. 

§  2.  Mode  of  obtaining  ozyg'.-n.  Oxygen  is  obtained 
in  a  variety  of  ways,  of  which  "it  will  suffice  to  mention 
the  following  four : 

1.  From  a   substance    called   Chlorate   of  potash  ;    by 
heating  it  in  a  retort  and  collecting  the  gas  which  is  giv- 
en off  by  means  of  the  pneumatic  tub. 
Fig.    LXI. 


*  From  a  Greek  word,  signify it  g  formation  of  acid. 


•OXYGEN.  51 

When  the  Chlorate  of  Potash  is  heated  it  fuses,  and 
gives  off  the  oxygen  in  a  very  pure  state,  which  is  then, 
through  the  pipe,  conveyed  to  the  receiver,  in  the  manner 
explained  in  the  Introduction,  page  30,  Fig.  XLIV. 

2.  From    a   substance   called    Red  Oxide  of  quicksil- 
ver.    The  process   is   nearly  the  same  as  that  just   de- 
scribed. 

3.  From    a   substance   called  Black  Oxide  of  manga- 
nese. 

4.  From  a  variety  of  growing  vegetables  when  exposed 
to  solar  light,  and  from  the  green  matter  formed  in  stag- 
nant pools,  when  immersed  in  water.     This  is  an  experi- 
ment requiring  no  other  apparatus  than  a  tumbler  filled 
with  water  ;  if  at  hand,  Priestley's  bell-glass  is  best  adapt- 
ed for   it,  having   a  contrivance  at  the  neck,  by  which 
means  the  gas  may  be  introduced  into  another  vessel  or  a 
bladder.     (See  Fig.  XLV,  page  30.) 

§  3.  Combinations  of  oxygen.  Oxygen  combines  with 
nearly  all  simple  and  compound  bodies.  The  process  by 
which  this  combination  is  effected  is  called  the  oxygena- 
tion  of  bodies.  This  oxygen ation  is  sometimes  accompani- 
ed by  the  phenomenon  of  fire,  (by  light  and  heat)  in  which 
case  it  is  termed  combustion.  The  products  of  the  differ- 
ent combinations  of  oxygen  with  other  elements  are  either 
oxides  or  acids  ;  according  to  the  different  proportions  in 
which  the  oxygen  combines  with  them. 

EXAMPLE. — Carbon  combined  with  oxygen  gives  1  oxide 
and  3  different  acids.  Sulphur  combined  with  oxygen  gives  4 
different  acids.  Iron  forms  with  it  2  different  oxides,  &c. 

§  4.  The  different  oxides  and  acids  arising  from  the  va- 
rious combinations  of  oxygen  with  other  substances,  have 
each  received  a  particular  name,  indicative  of  the  proportion 
of  oxygen  contained  in  the  combination.  The  oxides  are 
termed  Protoxides,  Deutoxidcs  and  Peroxides.  The  name 
of  Protoxide  is  given  to  the  smallest  quantity  of  oxygen  com- 
bined with  another  substance ;  that  of  Deutoxide  denotes 
the  next  greater  quantity  of  oxygen  combined  with  it ;  and 
the  name  of  Peroxide  is  applied  to  the  greatest  proportion 


52  OXY'GEN. 

of  oxygen  which  an  oxide  is  capable  of  holding.  With 
regard  to  the  acids,  we  are  in  the  habit  of  distinguishing 
them  by  iheir  terminations,  in  ic  or  ous  ;  or  by  putting 
the  Greek  preposition  hypo  (signifying  under)  before  the 
name  of  the  acid.  The  name  of  the  acid  ending  in  ic  in- 
dicates the  highest  degree  of  oxygenation  ;  that  termin- 
ating in  ous  indicates  the  next  lower  degree  ;  a  still  lower 
degree,  if  there  be  any,  is  expressed  by  the  preposition 
hypo. 

EXAMPLE. — The  gas  called  nitrogen  forms  with  oxgyen 
three  different  acids,  which,  according  to  the  degree  of  oxygen- 
ation (the  quantity  of  oxygen  contained  in  their  composition) 
are  called  nitric  acid  ;  nitrous  acid,  and  hypo  -nitrous  acid.  Ni- 
tric acid  indicates  the  highest  degree  of  oxygenation  ;  nitrous 
acid  the  next  lower,  and  hypo-nitrous  acid  the  lowest  degree. 

Theory  of  Combustion. 

§  5.  It  has  been  said  before  (§  3)  that  the  combination 
of  some  bodies  with  oxygen  is  accompanied  by  fire  —  in 
which  case  it  is  called  the  combustion,  or  burning  of  bodies. 
The  combustion  or  burning  of  bodies,  therefore  consists  in 
their  sudden  combination  with  oxygen.*  Every  body  capa- 
ble of  such  a  combination  is  called  a  combustible  sub- 
stance. 

Phlogiston  of  the  ancients.  —  The  ancient  chemists  ascribed 
the  process  of  combustion,  or  the  phenomenon  of  fire,  to  a  par- 
ticular substance  which  they  called  phlogiston.  But  this  the- 
ory has  long  ago  been  exploded  ;  and  it  is  now  generally  taken 
as  an  established  fact  that  this  phenomenon  is  produced,  as  we 
have  said  before,  by  the  sudden  union  of  oxygen  with  a  com- 
bustible body. 

§  6.  Degree  of  temperature  necessary  for  combustion. 
There  are  bodies  which  combine  with  oxygen  to  combus- 
tion without  being  previously  heated  (as  is,  for  instance, 
the  case  with  a  substance  called  sulphuretted  hydrogen)  ; 
most  bodies,  however,  require  for  this  purpose  a  certain  high 
degree  of  temperature. 

*  We  su.ill  se.3  hero.ifter  that  the  gas  termed  chlorine  is  in  a  cer- 
tain measure  capable  of  producing  similar  phenomena. 


•     OXYGEN.  53 

EXAMPLE.  —  Sulphur,  wood,  coal,  phosphorus,  &c,  must  first 
be  heated  to  a  certain  degree  of  temperature  before  they  ex- 
hibit the  phenomenon  of  fire.  But  when  these  bodies  are 
once  heated,  they  generally  give  out  sufficient  heat  to  keep  up 
the  degree  of  temperature  necessary  for  their  combustion. 

Fig.  LXII.        Fig.  LXHL 

The  chemical  process  of  a  burn- 
ing candle  (Fig.  LXII,)  or  lamp, 
(Fig.  LXIII,)  is  this  :  The  wick  a, 
is  lighted  by  a  piece  of  burning 
paper  or  wood.  By  this  means  the 
surrounding  particles  of  fat  or  oil 
are  heated  to  the  boiling  point, 
(Natural  Philosophy,  Chap.  VI,) 
and  thereby  decomposed  as  all  an- 
imal substances,  into  inflammable 
gases.  These  combine  with  the 
oxygen  of  the  atmosphere  and  pro- 
duce the  phenomenon  of  light, 
commonly  called  the^ame  of  the 
candle.  This  flame  gives  out  sufficient  heat  to  keep  the 
degree  of  temperature  necessary  for  the  decomposition  of 
another  portion  of  the  fat  or  oil ;  and  so  does  this  process 
continue  until  the  whole  candle  or  oil  is  exhausted. 

§  7.  Light  given  out  by  the  combustion  of  bodies,  The 
light  which  is  given  out  by  different  substances  during  the 
process  of  combustion  is  subject  to  variation  in  intensity 
and  color. 

EXAMPLES.  —  Phosphorus,  zinc,  and  arsenic  give  out  a  white 
light ;  the  flame  of  sulphur  is  blue  ;  that  of  selenium  azure  / 
&c« 

The  color  of  the  flame  does  not  only  depend  on  the 
burning  substance,  but  also  upon  the  degree  of  heat  pro- 
duced by  its  combustion.  Most  combustible  bodies  when 
moderately  heated  burn  with  a  yellow  or  blue  flame ;  par- 
ticularly if  there  be  no  draft  to  supply  the  flame  with  fresh 
quantities  of  oxygen. 

§  8.  Combustion  in  oxygen.  All  combustible  bodies  burn 
in  oxygen  with  increased  splendor. 

5* 


54 


OXYGEN. 


Fig.  LXIV. 


EXAMPLE.  —  A  small  piece  of  wax 
taper  with  its  flame  blown  out,  but 
its  snuff  still  red  hot,  when  immers- 
ed into  a  vessel  filled  with  oxygen, 
is  instantly  rekindled,  and  throws 
out  a  most  vivid  light.  -(See  Fig. 
LXIV.) 


Fig.  LXV. 

A  piece  of  sulphur  or  phosphorus,  let 
down  into  a  jar  filled  with  the  same  gas 
will  burn  with  indescribable  brilliancy. 
(See  Fig.  LXV.) 

In  order  to  perform  these  experiments  a 
common  bottle  or  jar  may  be  filled  with 
the  gas  by  means  of  the  pneumatic  tub. 
(Intr.  page  30.)  Through  the  cork  of  the 
bottle  a  piece  of  wire  may  be  made  to  pass, 
containing  at  its  lower  end  the  body  which  is  to  be  immersed. 
(See  the  next  figure.) 

ANOTHER  EXAMPLE.  — Iron,  which  only  burns  at  very  ele- 
vated temperatures,  needs  but  a  red  heat  to  burn  in  oxygen 
gas  with  a  light  which  is  almost  as  dazzling  and  insufferable 
to  the  eye  as  the  sun  itself. 

Fig.  LXV  I. 

A  faint  representation  of  it  is 
given  in  Fig.  LXIV.  A  piece  of 
piano-wire  spirally  twisted,  is  in- 
troduced air-tight  through  the 
cork,  a,  of  a  bell-glass  or  receiv- 
er filled  with  oxygen  gas.  To 
the  lower  end  of  this  wire  is  at- 
tached a  piece  of  thread,  touch- 
ed with  sulphur  or  wax,  to  ignite 
the  wire  in  the  first  instance. 
As  the  gas  is  a  little  heavier  than 
atmospheric  air,  its  escape  or 
mixing  with  the  atmosphere  is 
prevented  by  placing  the  receiv- 
er in  a  basin  filled  with  water.  If  we  were  to  employ  a  com- 


OXYGEN.  55 

mon  jar  for  the  same  experiment,  then  the  little  globulse  of 
melted  wire  which  drop  during  the  process  of  combustion, 
would  melt  the  glass,  or  if  the  bottom  of  the  vessel  be  thin, 
fuse  a  hole  through  it,  without  breaking  the  glass. 

Query —  What  do  all  these  examples  prove,  in  reference  to 
the  heat  produced  by  the  burning  of  substances  in  oxygen  gas  ? 
Ans. — These  examples  prove  that  the  heat  given  out  by  the 
combustion  in  oxygen  gas  is  incomparably  more  intense  than 
that  thrown  out  by  combustion  of  the  same  substances  in  atmos- 
pheric air.  Query  —And  what  would  become  of  our  grates, 
stoves,  or  iron  forges,  in  short,  of  all  the  labors  of  the  black- 
smith, if  our  globe  was  surrounded  by  pure  oxygen  ?  Ans. — 
Our  grates  and  stoves  would  burn  and  melt  the  moment  they 
would  get  red  hot ;  and  as  to  the  labors  of  the  black  smith, 
they  would  be  entirely  out  of  the  question  ;  —  for  in  order  to 
shape  iron,  it  must  first  be  made  red  hot  (it  being  exceedingly 
hard  in  its  natural  state);  and  the  moment  it  would  get  red 
hot  it  would  begin  to  burn  and  melt  into  balls. 

§  9.  If  the  whole  product  of  combustion  is  weighed  it  is 
always  found  to  be  heavier  than  the  substance  was  before 
the  combustion.  Thus,  when  a  piece  of  wire  is  .burnt  in 
oxygen  its  weight  is  found  to  increase  by  40  per  cent,  — 
that  is,  100  grains  of  iron  before  the  combustion,  weigh 
140  grains  after  it.  The  reason  of  this  change  in  the 
weightofiron,  is  because  40  grains  of  oxygen  gas  combined 
with  it  during  the  combustion.  A  similar  increase  of 
weight  is  noticed  in  all  bodies  which  are  burnt  in  oxygen 
gas,  and  corresponding  changes  take  place  at  every  com- 
bustion in  atmospheric  air.  To  this  general  rule  it  can- 
not be  objected  that  the  ashes  obtained  from  burning 
wood,  straw  or  other  substances  weigh  generally  much 
less  than  these  substances  did  before  they  were  burned  ; 
because  when  these  bodies  are  burnt  in  the  open  air,  we  do 
not  obtain  the  whole  product  of  their  combustion.  A  great 
quantity  of  inflammable  gas  which  is  always  given  off  dur- 
ing their  combustion,  escapes  through  the  chimney  or  in 
the  air.  But  when  these  are  collected  and  their  weight 
added  to  that  of  the  ashes,  then  the  sum  of  these  united 
weights  is  always  greater  than  that  of  the  wood,  straw,  or 
other  substance  before  the  combustion. 

§  10.    No  combustion  can  take  place  without  the  pres- 


56  O  X  Y  G  E  M  . 

etice  of  oxygen;*  the  process  of  combustion ,  therefore,  can 
only  be  continued  as  long  as  there  is  a  sufficient  quantity  of 
oxygen  to  support  it.  This  follows  immediately  from  what 
we  have  said  in  §  5.  For  if  every  combustion  consists  in 
the  combination  of  oxygen  with  a  combustible  substance, 
it  is  self-evident  that  no  such  process  can  take  place  un- 
less a  sufficient  quantity  of  oxygen  is  present.  Moreover 
we  can  mark  the  actual  consumption  of  oxygen  gas  during 
combustion  by  a  very  easy 

Fig.  LX VII.  EXPERIMENT. — Take  a  common 

bell-glass  or  receiver,  through  the 
cork  of  which  introduce  a  piece  of 
bent  wire,  supporting  at  its  lower  end 
a  small  lighted  candle,  a,  and  place 
the  whole  over  a  basin  of  water.  As 
the  candle  is  burning,  the  water  of 
the  basin  will  rise  in  the  receiver,  so 
that  if  a  small  scale  be  introduced 
into  the  latter,  the  rising  of  the 
water  will  indicate  the  quantity  of 
oxygen  consumed. 
Query — What  does  the  rising  of  the  water  in  the  receiver 
prove  ?  Jlns.  —  It  proves  that  a  portion  of  the  gas  in  the  re- 
ceiver is  consumed  by  the  flame  of  the  candle.  Query  —  Why  ? 
Ans.  —  Because  without  such  a  consumption  of  the  gas  no 
vacuum  could  be  created  in  the  receiver,  into  which  the  water 
could  be  forced  by  the  external  air. 

ANOTHER  EXPERIMENT.  —  Instead  of  oxygen,  fill  the  re- 
ceiver (in  the  last  figure)  only  with  common  atmospheric 
air.  The  burning  of  the  candle,  although  less  vivid,  will 
still  consume  a  portion  of  air  ;  the  water  will  still  rise  in  the 
receiver,  although  not  so  rapidly  nor  so  high  as  when  pure 
oxygen  is  employed ;  and  the  candle,  after  burning  more  and 
more  faint,  will  finally  become  extinguished.  When  the 
quantity  of  air  then  remaining  in  the  receiver  is  examinedj 
it  is  found  to  have  lost  just  y2^  of  its  volume,  which  is  ex- 
actly the  proportion  in  which  oxygen  is  contained  in  atmos. 

*  We  shall  see  in  future  that  a  few  substances  burn  faintly  in 
chlorine ;  but  this  can  hardly  be  considered  an  exception  to  the 
genera!  rule. 


OXYGEN. 


57 


phericair.  (See  §  1.)  A  burning  candle  now  introduced 
into  this  air  is  instantly  extinguished  ;  small  animals,  birds, 
frogs,  &c,  introduced  into  it  speedily  die  ;  in  short,  the 
remainder  of  the  air  in  the  receiver  is  totally  unfit  either 
to  support  combustion  or  the  process  of  respiration  of  liv- 
ing animals. 

Query — What  does  the  slower  burning  of  the  candle  in 
common  atmospheric  air  prove  ?  Jlns.  —  It  proves  that  the 
vividness  and  splendor  of  the  combustion  depend  on  the  great- 
er or  less  quantity  of  oxygen  which  is  consumed  ?  Ques.  — 
But  why  does  not  the  water  rise  as  high  in  the  receiver  as 
when  pure  oxygen  is  employed  ?  *Qns.  —  Because  the  whole 
quantity  of  air  in  the  receiver  is  not  consumed  by  the  burning 
of  the  candle  ;  but  only  that  portion  of  it  which  is  pure 
oxygen.  Ques.  —  And  why  does  the  candle  become  extin- 
guished, when  -j-2^  of  the  whole  air  originally  contained  in  the 
receiver  are  consumed?  Jlns.  —  Because  the  air  which  then 
remains  in  the  receiver  is  destitute  of  oxygen  gas,  and  is  on 
that  account  incapable  of  supporting  either  combustion  or  res- 
piration. Ques.  —  What,  therefore,  is  necessary  in  order 
that  a  complete  combustion  of  bodies  shall  take  place  in  at- 
mospheric air  or  oxygen  ?  Ans.  —  It  is  necessary  that  a  fresh 
quantity  of  atmospheric  air  or  oxygen  should  be  supplied, 
while  the  process  of  combustion  is  going  on. 

Fig.  LXVIII. 

^^  ANOTHER  EXAMPLE.  —  A 

burning  candle  introduced 
into  the  receiver  of  an  air- 
(pump  (Fig.  LXVIII,)  burns 
'slower  and  slower  as  the  air 
in  the  receiver  becomes  more 
and  more  exhausted,  (Natural 
Philosophy,  Chap.  V,)  until 
finally  it  becomes  wholly  ex- 
tinguished. A  small  animal 
or  a  bird  introduced  instead' 
of  the  candle  will  be  thrown 
into  convulsions  and  expire. 
Gunpowder,  phosphorus,  and 
sulphur  will  cease  to  burn  in 
the  vacuum.  An  improper 
mixture  of  gases,  in  which 
the  oxygen  is  not  contained  in  a  sufficient  proportion,  produces 
the  same  effect ;  because  it  is  then  unfit  to  support  the  pro- 
cess of  combustion  or  respiration. 


58  OXYGEN. 


—  What  remarkable  coincidence  do  you  here  observe 
between  the  process  of  respiration  and  combustion  ?  Jins.  — 
That  oxygen  is  alike  indispensable  to  the  one  and  the  oth- 
er ;  for  whenever  the  process  of  combustion  discontinues  from 
want  of  oxygen,  that  of  respiration  ceases  also.  Ques.  — 
What  mode,  therefore,  may  be  devised  for  finding  out  wheth- 
er a  certain  mixture  of  gases  is  respirable  or  not?  Jlns.  — 
A  burning  candle  may  be  introduced  in  it;  when  it  continues 
to  burn  the  gas  will  be  respirable  ;  when  it  is  extinguished,  or 
burns  but  dimly,  then  the  gas  will  not  be  fit  for  respiration. 

This  is  a  convenient  way  for  trying  the  air  in  old  wells 
or  in  caverns,  and  cannot  be  too  urgently  recommended  ; 
many  lives  having  been  lost  by  omitting  this  caution. 

§11.  The  quantity  of  air  or  oxygen  necessary  for  the 
continuance  of  the  process  of  combustion  is  supplied  ei- 
ther by  a  draft  or  by  means  of  bellows.  We  know  from 
Natural  Philosophy,  (Chap.  V,)  that  when  a  body  is 
burning,  the  heated  air  which  surrounds  it  becomes  spe- 
cific, lighter,  and  ascends,  while  a  fresh  portion  of  exter- 
nal air  rushes  in  its  place.  This  is  called  a  draft.  To 
facilitate  it  we  build  fire-places  and  chimneys.  The  high- 
er the  chimney  is,  or  the  greater  the  difference  between 
the  temperature  of  the  air  ascending  in  the  chimney,  and 
that  of  the  surrounding  atmosphere,  the  greater  is  the 
draft,  and  the  better  therefore  will  the  fire  burn. 

Query  —  Could  you  now  devise  a  means  for  improving  smok- 
ing fire-places?  */2ns.  —  Yes.  Smoking  fire-places  might  be 
improved  by  heightening  the  chimneys.  Ques.  —  Why? 
Jlns.  —  Because  this  would  create  a  better  draft,  adding  there- 
by continually  a  new  quantity  of  oxygen  to  the  fire,  and  caus- 
ing by  that  means  a  more  perfect  combustion.  Query  —  And 
can  you  now  explain  the  reason  why  an  Argand's  lamp  (see 
Fig.  XXXV,  page  24,)  burns  brighter  when  the  glass  is  put  on, 
than  without  it  ?  Ans.  —  Because  the  glass  serves  in  this  in- 
stance as  a  sort  of  chimney,  which  increases  the  draft, 

§  12.  Extinguishing  of  Jire.  Fire  is  extinguished,  as 
we  have  seen,  by  abstracting  the  oxygen  from  the  burning 
substance,  or,  which  amounts  to  the  same  thing,  by  ex- 
cluding the  atmosphere  from  the  burning  substance.  This 
is  effected  by  covering  the  combustible  substance  with  an- 
other substance,  through  which  the  oxygen  of  the  atmos- 


OXYGEN.  59 

phere  cannot  penetrate.  For  this  purpose  we  commonly 
employ  water,  merely  because  it  is  readiest  procured  ;  but 
then  it  is  necessary  to  use  a  sufficient  quantity  to  cover 
the  whole  surface  of  the  burning  body. 

Small  quantities  of  water  are  of  little  or  no  use  in  confla- 
grations ;  but,  on  the  contrary,  rather  contribute  to  increase 
them  ;  because  red  hot  coal,  as  we  shall  see  hereafter,  decom- 
poses water  into  hydrogen  and  oxygen  ;  the  latter  of  which 
substances  adds  necessarily  to  the  rapidity  of  the  flames. 
(§  7.)  It  is  for  this  reason  blacksmiths  are  in  the  habit  of  wet- 
ting their  coal  before  using  it. 

§  13.  It  has  already  been  observed  that  some  sub- 
stances combined  with  oxygen  without  the  phenomenon 
of  fire.  This  is  the  case  when  the  combination  takes 
place  very  slowly. 

It  is  in  this  manner  many  of  the  metals  combine  with  oxy- 
gen at  the  mean  temperature  of  the  atmosphere.  Sodium, 
potassium,  iron,  lead,  tin  and  manganese  are  oxidized  with- 
out giving  out  any  observable  degree  of  heat  or  light. 
Another  substance,  (which  we  shall  become  acquainted  with 
in  the  course  of  this  work)  termed  nitric  oxid,  combines  with 
oxygen  at  the  greatest  cold  ;  while  carbon  unites  with  it  at 
a  temperature  exceeding  (556  degrees  Fahrenheit,  without 
the  phenomenon  of  fire. 

§  14.  It  remains  for  us  to  speak  of  the  process  of 
desoxidation,  which  consists  in  separating  the  oxygen  from 
a  body  with  which  it  is  combined.  It  is  effected  two 
ways : 

1.  By  Jicat.     This  is  the   case  with  the  oxides  of  the 
precious  metals,  silver,  gold,  platinum,  &c. 

2.  By  the  admixture  of  a  third  substance,  commonly 
potassium,  for  which  oxygen  has  a   great   affinity.     (See 
Art.   Potassium,  Chap.  III.) 

The  different  combinations  of  oxygen  with  other  substances 
will  be  spoken  of  when  treating  of  these  substances. 

75.     Hydrogen. 

§  15.  When  water  is  subjected  to  the  action  of  Gal- 
vanic Electricity,  it  is,  as  we  have  had  occasion  to  remark 


60 


HYDROGEN. 


before,  decomposed  into  two  distinct  gases,  whose  proper- 
ties are  in  every  respect  directly  opposite  to  each  other. 
These  two  gases  are  Hydrogen*  and  Oxygen. 
Fig.  LXIX. 

The  experiment  may  be  made 
either  by  means  of  a  voltaic  pile, 
(Fig.  LXIX,)  or  by  a  trough  bat- 
tery (see  Fig.  L1X,  page  40). 
When  the  voltaic  pile  is  employ- 
ed, the  apparatus  represented  in 
Fig.  LXIX,  in  which  the  two  poles 
A,  B,  are  introduced  into  a  cylin- 
drical tube  filled  with  water,  is 
very  convenient. 
Fig.  LXX. 

When  the  trough-battery  is  used, 
the  two  poles  of  the  battery  are 
introduced  into  a  bent  glass  tube, 
shaped  like  a  V,(see  Fig.  LXX.) 
This  tube  is  first  filled  with  water 
and  then  inverted  and  held  over 
a  basin  filled  with  the  game  liquid, 

which   in  this  case    answers  the  purpose  as  a  pneumatic 
tub.    The  two  gases,  hydrogen  and  oxygen,  inio  which  the 
water  is  decomposed,  rise  in  little  bubbles  to  the  top,  but 
are  in  both  instances  obtained  in  a  state  of  mixture. 
Fig.  LXXL 

To  obviate  this  we  make  use  of  an  ap- 
paratus represented  in  Fig.  LXXL  The 
two  poles  of  the  galvanic  battery  are 
brought  in  contact  with  two  brass  knobs, 
A  and  B,  which  by  means  of  thin  platina 
wires  melt  into  the  glass,  communicate 
with  the  water  in  the  bent  tube.  Each 
of  the  extremities  of  the  tube  is  fitted  to  a 
small  jar,  closed  with  a  stopper,  and  the 
whole  apparatus  is  filled  with  water.  When  the  battery  is 
set  in  motion,  the  water  in  the  tube  becomes  decomposed 

*  From  a  Gteek  word,  signifying  formation  of  water. 


HYDROGEN.  61 

and  forms  two  distinct  gases  ;  but  by  a  fixed  law  of  elec- 
trical attraction  (mentioned  before  in  Intr.  page  41,)  one  of 
these  gases,  the  hydrogen,  always  collects  about  the  nega- 
tive or  copper  pole,  and  on  that  account  rises  in  little  bub- 
bles in  the  jar  which  is  connected  with  that  pole  ;  while 
the  oxygen  follows  the  electric  attraction  of  the  positive  or 
zinc  pole,  and  collects  in  the  other  jar.  By  tho  aid  of  this 
apparatus  the  two  gases  are  obtained  separately,  and  may 
be  examined  for  the  sake  of  various  chemical  purposes. 
What  is  most  remarkable  about  this  decomposition  of  wa- 
ter is,  that  the  volume  of  hydrogen  gas  thence  obtained,  is 
always  exactly  double  that  of  the  oxygen,  from  which  we 
infer  that  in  water  two  volumes  of  hydrogen  are  combined 
with  one  volume  of  oxygen.  But  about  this  we  shall  soon 
have  occasion  to  say  more. 

Properties  of  Hydrogen  Gas. 

§  16.  When  hydrogen  gas  is  examined  in  its  pure 
state  (as  obtained  from  the  decomposition  of  water  by  gal- 
vanic electricity),  it  is  found  to  be  destitute  of  color,  taste, 
or  smell.  It  is  much  lighter  than  atmospheric  air,  only 
one  sixteenth  as  heavy  as  oxygen  —  and  indeed  the  light- 
est ponderable  substance  in  nature.*  It  is  highly  com- 
bustible (§  5),  and  when  ignited  (kindled)  by  a  burning 
substance,  or  an  electric  spark,  burns  with  a  yellowish 
flame  and  gives  out  great  heat.  It  is  unfit  for  respiration, 
although  it  may  be  breathed  for  a  short  time  with  impuni- 
ty. It  is  equally  unfit  to  support  the  process  of  combus- 
tion, although  it  is,  itself,  a  highly  combustible  substance. 
A  burning  substance  immersed  in  it,  is  instantly  extin- 
guished. 

*  In  speaking  of  the  speci6c  gravity  of  bodies,  we  always  suppose 
the  pressure  of  the  atmosphere  equal  to  30  inches  of  quicksilver,  and 
its  temperature  equal  to  60  degrees  of  Fahrenheit's  thermometer.-— - 
(See  Grund's  Natural  Philosophy,  article  Gravity.) 

6 


HYDROGEN. 


Fig.  LXXII. 

EXPERIMENT.  —  If  a  lighted  candle  or 
wax  taper  is  brought  near  the  mouth  of 
a  bottle  or  jar  filled  with  hydrogen  gas, 
the  gas  will  instantly  ignite  at  the  mouth 
of  the  bottle  ;  but  the  taper  itself,  when 
deeper  immersed,  will  be  extinguished. 
When  the  taper  is  drawn  out,  it  will  again 
be  ignited  by  the  burning  hydrogen  at 
the  mouth  of  the  bottle.  This  experi- 
ment may  be  repeated  a  number  of  times, 
until  the  gas  is  entirely  exhausted. 

Query  —  What  does  the  inflammation 
(ignition)  of  the  gas  at  the  mouth  of  the 
bottle  prove  ?  Jlns.  —  It  proves  that  hydrogen  is  a  highly  com- 
bustible substance.  Query  —  And  what  does  the  extinguish- 
ing of  the  candle  when  immersed  in  hydrogen,  show  ?  Ans. — 
It  shows  that  although  hydrogen  is,  itself,  a  highly  inflamma- 
ble gas,  it  is  not  capable  to  support  the  combustion  of  other 
substances. 

Fig.  LXXIH. 

ANOTHER  EXPKRIMENT,  which  shows  that  the 
specific  gravity  of  hydrogen  is  much  less  than 
that  of  atmospheric  air,  may  be  performed  by 
lAfilling  two  common  beer  or  wine  glasses  (Fig. 
LXXIII,)  with  this  gas,  and  placing  them,  one 
with  its  open  mouth  up,  and  the  other  down. 
In  a  few  minutes  the  gas  will  have  entirely  es- 
caped from  the  glass  B,  which  is  placed  with 
its  mouth  up  —  but  it  will  still  be  found  in  the 
one,  A,  which  has  its  mouth  turned  downwards. 
This  may  be  easily  ascertained  by  applying  the  flame  of  a  can- 
dle to  the  mouth  of  each  glass.  The  hydrogen  contained  in 
the  glass,  A,  will  burn  ;  but  in  B  there  will  be  nothing  but  at- 
mospheric air,  which  of  course  will  not  ignite. 

Query  —  Why  has  the  gas  escaped  from  the  glass  which 
has  its'mouth  up?  Jlns.  —  Because  hydrogen  being  much 
lighter  than  atmospheric  air,  would  naturally  ascend  as  a 
piece  of  wood  does,  when  placed  under  water.  Query  —  But 
why  does  the  gas  remain  in  the  glass  with  its  mouth  down  ? 
Ans.  —  Because  a  vessel  filled  with  hydrogen,  having  its 
mouth  turned  downwards,  may  be  considered  as  closed ;  for 
the  escape  of  the  gas  is  prevented  from  above,  and  the  pressure 
of  the  heavier  atmosphere  does  not  permit  it  to  descend  below. 


HYDROGEN. 


63 


Fig.  LXXIV. 

Query  —  In  what  manner  then  can  you  transfer 
hydrogen  gas  from  one  vessel  to  another  ?  Ans.  — 
It  is  only  necessary  to  place  the  mouth  of  an  open 
vessel  or  receiver,  B,  (Fig.  LXXIV,)  over  the  open 
neck  or  mouth  of  another  vessel  or  jar,  A,  rilled 
with  the  gas.  The  gas  will,  on  account  of  its  levity, 
escape  thrrough  the  neck  of  the  vessel,  A  (through 
which,  for  convenience  sake,  an  open  tube  may  be 
made  to  pass),  and  ascend  in  the  receiver  B,  from 
which  it  will  expel  the  atmospheric  air. 


ANOTHER  EXPERIMENT,  which  shows  the  levity  of  hydrogen 
gas,  and  at  the  same  time  enables  us  to  find  its  specific  grav- 
ity is  the  following. 

LXXV. 

Take  an  open  jar  or  phial,  C, 
which  attach  to  one  scale  of  a 
common  balance  with  its  mouth 
downwards,  and  set  the  whole 
apparatus  in  equilibrium  by  add- 
ing as  much  weight  to  the  scale 
B,  £s  is  necessary  for  that  pur- 
pose. Conduct  hydrogen  from  a 
Florence  flask,  F,  into  the  jar. 
In  proportion  as  the  hydrogen 
ascends  through  the  pipe,  P, 
and  expels  the  atmospheric  air 
from  C,  the  scale  B  will  sink ; 
and  by  marking  the  weight  which 
it  is  finally  necessary  to  place 
upon  A,  in  order  to  restore  the  equilibrium,  we  determine  the 
difference  between  the  weight  of  atmospheric  air  previously 
contained  in  it,  and  that  of  an  equal  volume  of  hydrogen  gas. 
This  will  enable  us  to  find  the  specific  gravity  of  hydro- 
gen. For  when  the  weight  of  the  atmospheric  air  in  the 
jar  A  is  known,  (which  may  be  easily  obtained  by  finding 
what  the  jar  weighs  when  the  air  is  exhausted  from  it)  it 
is  only  necessary  to  find  the  weight  of  an  equal  volume 
of  hydrogen  ;  which  we  obtain  by  subtracting  the  loss  of 
the  jar  when  filled  with  that  gas,  from  the  weight  of  the 


64  HYDROGEN. 

atmospheric  air  contained  in  it.  The  weight  of  the  gas 
thus  found,  divided  by  that  of  atmospheric  air,  gives  the 
specific  gravity  of  hydrogen.  This  you  will  probably  bet- 
ter understand  from  an 

EXAMPLE.  —  Supposing  the  jar,  when  the  air  is  exhausted 
from  it,  loses  14T4o-  grains  ;  supposing  further,  that  by  intro- 
ducing the  hydrogen,  instead  of  the  atmospheric  air,  the  jar 
loses  13T4<y  grains.  Query.  —  What  is  the  specific  gravity  of 
hydrogen  ?  Ans.  —  By  the  first  supposition  it  is  evident  that 
the  atmospheric  air  which  is  contained  in  the  jar  weighs  14^y 
grains  ;  by  the  second  it  is  plain  that  the  weight  of  an  equal 
volume  of  hydrogen  is  only  1  grain  ;  because  1  grain  and  13^ 
grains  (the  difference)  make  14TV  grains ;  consequently  the 
specific  gravity  of  atmospheric  air  is  to  that  of  hydrogen  as 
14^7  is  to  1 ;  or  in  other  words,  atmospheric  air  is  more  than 
14  times  heavier  than  hydrogen. 

Dividing  1  by  14T%,  or,  which  is  the  same,  •}•§•  by  -Y^S  we 
obtain  Tj°¥  =  0,069  for  the  specific  gravity  of  hydrogen  ex- 
pressed in  decimals. 

Fig.  LXXVI. 

ANOTHER  EXPERIMENT,  which  shows  the 
levity,  and  at  the  same  time  the  combustiblity 
of  hydrogen  gas,  is  represented  in  Fig.  LXXVI. 
A  jar  with  a  narrow  tube  passed  air-tight 
through  its  cork,  is  filled  with  hydrogen,  and 
the  flame  of  a  candle  applied  to  the  open 
end  of  the  tube.  The  gas,  which  by  its  lev- 
ity escapes  through  the  tube,  will  instantly  be 
kindled  and  throw  out  great  light.  As  the  gas 
is  gradually  ascending,  it  nourishes  the  flame, 
which  will  continue  to  burn  until  the  whole 
quantity  of  hydrogen  is  consumed. 

§  17.  The  decomposition  of  water  by  galvanic  elec- 
tricity is  not  the  only  means  of  obtaining  hydrogen  gas, 
for  in  this  manner  it  is  only  obtained  in  small  quantities  ; 
although  in  its  purest  state.  There  are  yet  two  principal 
ways  of  procuring  this  gas,  which  we  shall  now  ex- 
plain. 

The  first  is  by  suffering  the  hot  vapors  from  boiling  water 
to  pass  through  an  iron  gun-barrel  ;  by  which  means  the 
steam  becomes  decomposed  into  hydrogen  and  oxygen  gas ; 
the  oxygen  combines  with  the  iron  and  the  hydrogen  is 


HYDROGEN. 


65 


Fig.  LXXVII. 
A 


fiven  off.  This  is  the  commonest  way  of  obtaining  it. 
ig.  LXXVII  represents  the  apparatus  used  for  this  pur- 
pose. B  C  represents  the  gun-barrel,  which  contains  in 
its  centre  a  piece  of  coiled  iron-wire,  and  is  placed  across 
a  portable  wind-furnace,  for  the  purpose  of  heating  it  red 
hot.  The  retort,  G,  the  neck  B,  of  which  fits  air-tight  into 
the  barrel,  JB  C,  is  partly  filled  with  water  which  is  heated 
and  converted  into  steam  by  means  of  an  Argand's  or  spir- 
it lamp,  L.  The  steam  thus  formed  is  conducted  into  the 
barrel,  where  by  the  affinity  of  the  red  hot  iron  for  oxygen, 
it  is  decomposed  into  its  gaseous  elements,  oxygen  and 
hydrogen  ;  the  former  combining  with  the  iron,  and  the 
hydrogen  passing  through  the  pipe  P,  and  the  pneumatic 
tub,  into  the  receiver,  R. 
Fig.  LXXVIII. 

A  still  more  convenient  way  of 
obtaining  hydrogen  gas  in  great 
quantities  is  the  second,  repre- 
sented in  the  adjoining  figure 
LXXVIII.  It  consists  in  decom- 
posing water  by  means  of  zinc* 
and  sulphuric  acid.  For  this  pur- 
pose a  few  small  pieces  of  zinc,  and 
about  a  gill  of  water  with  nearly  one  fifth  as  much  sulphuric 
acid,  are  placed  in  a  common  Florence  flask  F,  through 
the  neck  of  which  a  small  pipe,  P,  leads  to  the  receiver,  R. 
The  hydrogen  is  in  this  case  formed  by  the  decomposition 
of  water  by  the  joint  action  of  the  zinc  and  the  sulphuric 

*  Iron  filings,  nails,  or  tacks,  are  also  frequently  used  for  the  same 
experiment,  instead  of  the  zinc. 

6* 


66  HYDROGEN. 

acid.  This  is  effected  by  a  predisposing  affinity  of  the 
acid  for  a  combination  of  oxygen  and  zinc,  in  the  manner 
explained  in  the  Introduction,  page  9.  The  metal  attracts 
the  oxygen  of  the  water  ;  and  is  in  this  state  dissolved  by 
the  acid,  setting  the  hydrogen  free,  which  will  escape 
through  the  pipe  P,  into  the  receiver.  This  is  one  of 
the  cheapest  and  quickest  ways  of  obtaining  hydrogen  in 
large  quantities. 

Qweri/—  Which  of  the  substances  here  enumerated  exer- 
cises a  predisposing  affinity  for  the  oxygen?  Jlns.  —  The 
acid ;  because  it  predisposes  it  for  a  combination  with  the 
zinc. 

§  18,  Application  of  hydrogen  gas  to  Aerostatics. 
The  great  levity  of  hydrogen  gas  has  given  rise  to  one 
of  the  boldest  undertakings  which  ever  characterized  hu- 
man intrepidity  —  that  of  attempting  to  navigate  the  atmos- 
phere. A  small  ball  filled  with  hydrogen,  provided  it  be 
not  made  of  too  heavy  a  material,  will  be  lighter  than 
the  atmospheric  air  which  surrounds  it,  and  will  therefore 
be  forced  upwards  by  the  pressure  of  the  atmosphere.  This 
you  may  see  from  the  following 

Fig.  LXXIX.  EXPERIMENT.  —  Fill  a 

bladder  with  hydrogen 
gas  (how  this  is  done  by 
means  of  Priestley's  bell- 
glass,  has  already  been 
explained  in  the  Intro- 
duction, page  31);  in- 
sert a  narrow  pipe  into 
the  neck  of  the  blad- 
der, and  dip  its  mouth 
in  a  solution  of  soap  and  water ;  you  may  then  open  the  stop- 
cock and  by  squeezing  the  bladder  gently,  in  order  to  force 
the  gas  into  the  solution,  small  bubbles  will  be  formed,  which 
will  rapidly  ascend  in  the  air. 

Upon  this  experiment  is  founded  the  construction  of 
balloons  for  ascending  in  the  air.  The  whole  consists  in 
confining  hydrogen  gas  in  a  spherical  cover,  which  must 
be  sufficiently  thin  and  light,  in  order  that  with  the  hy- 
drogen gas  which  it  contains,  it  shall  weigh  less  than  the 
quantity  of  atmospheric  air  which  it  displaces  (Natural 


PYDROGEN.  67 

Philosophy,  Chap.  IV).  For  small  experiments,  a  bal- 
loon may  be  made  of  thin  letter-paper  ;  but  then  it  must 
at  least  have  from  6  to  7  inches  diameter,  otherwise  it  will 
not  rise.  Such  a  balloon  may  weigh  from  35  to  36  grains, 
and  contain  about  5  grains  of  hydrogen.  This  will  be 
sufficient  for  its  ascent,  because  its  whole  weight  will  only 
be  little  over  40  grains,  whereas  the  quantity  of  atmos- 
pheric air  which  it  displaces  is  more  than  50  grains.  If 
the  balloon  is  destined  to  draw  up  other  heavy  bodies,  then 
it  requires,  of  course,  a  much  larger  diameter.  The  cover 
is  then  made  of  varnished  silk,  in  order  that  the  exterior 
air  may  be  completely  excluded  from  it.  A  balloon  of  20 
Fig.  LXXX.  feet  in  diameter  may  contain  4190  cubic 
feet  of  hydrogen  gas,  and  will  be  capable, 
in  addition  to  its  own  tegument,  to  carry 
with  it  255  Ibs.  of  other  substances,  such 
as  ropes,  and  a  small  boat  in  which  a  man 
may  be  seated  without  inconvenience.  If 
the  balloon  is  30  feet  in  diameter  then 
it  may  contain  14, 142  cubic  feet  of  hy- 
drogen gas,  and  carry  a  burthen  of  near- 
ly 1000  Ibs.  Several  persons  may  then 
be  seated  in  the  boat,  or  basket,  attached 
to  the  balloon,  and  ascend  several  thou- 
sand feet  in  the  atmosphere  with  astonishing  rapidity. 

The  hydrogen  gas  prepared  for  this  purpose,  is  generally 
obtained  from  a  mixture  of  iron  or  zinc  (commonly  the  former) 
with  sulphuric  acid  and  water —  12  oz.  of  iron  and  as  much 
sulphuric  acid,  with  2  Ibs.  of  water  are  supposed  to  yield  1 
cubic  foot  of  the  gas. 

Mixture  of  Hydrogen  with   Oxygen  —  Inflammable,  gas. 

§  19.  Hydrogen  mixes  with  oxygen  in  all  proportions  ; 
and  such  is  the  affinity  between  these  two  substances  that 
although  hydrogen  is  16  times  lighter  than  oxygen,  it  re- 
mains throughout  equally  diffused  in  oxygen,  contrary  to 
the  laws  of  aerostatics  (see  Natural  Philosophy,  Chap. 
IV).  This  may  easily  be  shown  by  the  following 
!o  nsi'I'Mie  j-?'?  v.5.'xv«i  &v/  i;yu? 


O  HYDROGEN. 

Fig.  LXXXI  EXPERIMENT.  —  Take  two  glass  phials,  a,  b, 
into  the  corks  of  which  insert  a  narrow  glass 
tube,  several  inches  long.  Fill  one  of  these 
phials  with  oxygen  and  the  other  with  hydro- 
gen. Place  that  which  is  filled  with  oxygen 
with  its  mouth  upwards  and  insert  in  it  the 
cork  with  the  tube  ;  the  second  cork  at  the 
other  end  of  the  tube,  fit  to  the  mouth  of  the 
phial  filled  with  hydrogen  gas,  which  must  be 
placed  with  its  mouth  downward.  Now  ac- 
cording to  the  laws  of  gravity,  the  oxygen, 
which  is  the  specific  heavier  body,  ought  to 
remain  in  the  lower  phial,  and  the  hydrogen 
ought  to  remain  in  the  upper  ;  but  quite  the 
reverse  takes  place.  The  hydrogen  decends, 
and  the  oxygen  ascends,  although  oxygen  is  16  times  heavier 
than  hydrogen.  After  several  hours  the  two  gases  will  be 
equally  diffused  in  both  phials  ;  and  when  a  light  is  applied  to 
either  of  them  an  explosion  will  take  place,  which  will  be 
strongest  and  loudest  when  the  two  gases  are  mixed  in  the 
proportion  of  two  volumes  of  hydrogen  with  one  of  oxygen. 
Such  a  mixture  of  hydrogen  and  oxygen  is  called  inflammable 
gas.  The  product  of  its  combustion,  when  ignited  by  an 
electric  spark,  or  the  flame  of  a  candle,  is  water.  Hence  it  is 
not  only  in  our  power  to  decompose  water  into  oxygen  and  hy- 
drogen, but  we  can  also  reproduce  it  by  the  combination  of 
hydrogen  with  oxygen  in  a  proper  proportion. 

Several  chemists  have  attempted  to  account  for  the  explo- 
sion which  accompanies  the  combustion  of  inflammable  air. 
A  very  plausible  reason  on  this  subject  is  given  by  Mr  Schubert, 
Professor  of  Chemistry  in  Berlin.  He  attributes  the  explo- 
sion to  the  steam  which,  in  his  opinion,  is  forming  during  the 
combustion.  For  the  heat  which  is  given  off  when  the  gas  is 
ignited  is  so  great  thfct  the  water  which  is  formed  is  instantly 
converted  into  steam  ;  this  expands  itself  suddenly  ;  but  upon 
being  brought  in  contact  with  the  colder  air  is  suddenly  con- 
densed and  creates  a  vacuum,  into  which  the  surrounding  air 
rushes  with  great  violence. 

§  20.  When  one  volume  of  hydrogen  gas  is  mixed  with 
two  volumes  of  atmospheric  air,  another  inflammable  gas  is 
formed,  whose  effects,  however  are  much  inferior  to  those 
of  the  mixture  we  have  just  spoken  of. 


^YDROGEN. 


69 


Fig.  LXXXII. 

EXPERIMENT.  —  Take  a  hollow  tin 
vessel,  shaped  as  represented  in  figure 
LXXXII,  and  fill  it  with  hydrogen  gas. 
Fit  a  cork  to  its  mouth,  and  provide  it  in 
T  with  a  touch-hole.  When  the  flame 
of  a  candle  or  an  electric  spark  is  appli- 
ed to  the  touch-hole  T,  the  cork  will  be 
driven  out  with  considerable  force  and 
with  a  loud  report.  This  apparatus 
has  received  the  name  of  the  Hydrogen- 
gun. 

Query.  — What  is  the  probable  reason  of  the  cork  being 
so  violently  thrown  out,  by  the  combustion  of  the  inflamma- 
ble gas  in  the  gun  ?  Ans.  —  Because  by  the  combustion  of 
the  hydrogen  gas,  water  is  formed  ;  which,  owing  to  the  great 
heat  given  out,  is  instantly  converted  into  steam  ;  and  proba- 
bly expanded  to  such  a  degree  as  not  only  to  make  up  for  the 
condensation  of  the  gases,  (which  have  been  consolidated  into 
water)  but  also  to  exercise  a  considerable  pressure  upon  the 
cork,  which  is  by  that  means  expelled. 

From  what  we  have  said  of  the  combustibility  of  hydrogen 
gas,  and  its  inflammable  mixture  with  atmospheric  air  —  we 
may  perhaps  be  able  to  explain  the  following 

Fig.  LXXXIII. 

EXPERIMENT.  —  Take    a    common    Florence 
flask  (see  Fig.  LXXXIII,)  which  either  fill  with 
hydrogen  gas,  or   with  zinc,  sulphuric    acid    and 
water,  in  order  to  produce  hydrogen  gas  in  it. 
Through  the  cork  of  this  phial  pass  a  small,  nar- 
row tube,  through  which  the  gas  is  allowed  to  es- 
cape ;  light  the  gas  at  the  mouth  of  the  pipe,  and 
introduce  the  flame  in  a  glass  tube  of  sufficient 
diameter.     As  the  hydrogen  is  burning  in  the 
tube  musical  sounds  will  be  produced  which  will 
be  grave  or  acute,  according  as  the  tube  is  long 
or  short,  or   as  the  flame  is  deeper  immersed  in 
it.     Some   philosophers    consider   these   sounds 
as  a  continued  series  of  explosions  in  the  tube  : 
others  consider  them  occasioned  by  currents  of 
atmospheric  air  which  are   partly  produced  by  the  consump- 
tion of  oxygen,  and  partly  by  the  expansion  and  contraction  of 
the  heated  air  and  steam  in  the  tube. 
Great  caution  must  be  used  not  to  light  the  gas  too  soon, 


70 


H  Yf  D  R  O  G  E  N . 


but  to  wait  until  the  ascending  hydrogen  has  expelled  all  the 
atmospheric  air  in  the  tube,  otherwise  inflammable  air  would 
be  formed  which  would  explode  and  burst  the  tube,  and  per- 
haps injure  the  experimenter. 

When  soap  bubbles  are  blown  with  inflammable  air  (a 
mixture  of  hydrogen  and  oxygen)  instead  of  hydrogen, 
(see  fig.  LXXIX,  page  66,)  and  when  floating  in  the  air 
are  touched  by  the  flame  of  a  candle,  they  give  a  report 
as  loud  as  a  gun,  and  sometimes  even  more  loud  and 
stunning. 

Fig.  LXXX1V. 

§21.  A  most  impor- 
tant application  of  the 
properties  of  inflamma- 
|f  ble  air  to  chemical  pur- 
poses is  Hare's*  oxy-hy- 
drogen  blow-pipe.  It 
consists  of  two  air  or  gas- 
holders, A,  B,  of  which 
one  is  filled  with  oxy- 
gen, and  the  other  with 
hydrogen.  The  two 
tubes,  L  and  1,  commu- 
nicate with  these  gas- 
holders, have  a  common 
opening,  and  are  each 
provided  with  a  turn- 
cock, G,  g,  to  regulate  the  discharge  of  the  gases,  either 
jointly  or  separately,  and  in  any  proportion  we  please.  The 
substance,  which  is  to  be  exposed  to  the  action  of  this  appa- 
ratus, is  commonly  placed  upon  a  piece  of  charcoal  directly 
under  the  common  opening.  The  way  of  using  this  appa- 

*  DrR.  Hare,  of  Philadelphia,  was  the  first  who  suggested  the  idea 
of  constructing  a  blow-pipe  with  a  mixture  of  hydrogen  and  oxygen. 
Long  after  him,  in  1816,  (Hare  published  his  discovery  in  1802,) 
Newman,  an  English  chemist,  constructed  the  compound  blow-pipe, 
described  on  page  72,  Fig.  LXXXV.  But  Prof.  Hare's  apparatus 
has  the  vast  advantage  of  being  safe,  convenient,  and  much  less  lia- 
able  to  the  dreadful  accidents  which  have  already  but  too  frequently 
occurred  with  Newman's  apparatus, 


HYDROGEN.  71 

ratus  is  this.  When  the  two  gas-holders,  A  and  B, 
are  filled  with  hydrogen  and  oxygen  respectively,  (for  which 
purpose  both  gas-holders  may  be  fitted  to  a  wooden  tub  or 
cistern,  filled  with  water)  the  funnels,  F  f,  are  filled  with 
water,  which,  when  the  stop-cocks,  m,  »,  are  opened, 
is  suffered  to  descend  through  the  tubes,  T  and  t,  to  the 
bottom  of  the  gas-holders  ;  thereby  forcing  the  gas  upwards 
into  the  pipes,  L,  and  1.  (The  two  stop-cocks,  P,  p, 
serve  for  no  other  purpose  than  to  confine  the  gas  in  the 
holder  when  the  pipe  is  not  used.)  The  turn-cocks, 
G  and  g,  being  now  opened,  the  gas  is  ignited  at  their  com- 
mon opening,  and  the  jet  directed  to  the  substance  which 
is  to  be  exposed  to  its  heat. 

The  effects  of  this  apparatus  surpass  really  the  most 
sanguine  imagination  —  the  heat  produced  by  it  being  in 
some  instances  even  superior  to  that  produced  by  galvanic 
electricity.  Common  iron  wire  exposed  to  the  flame  does 
not  only  instantaneously  melt,  but  actually  boils  like  liquid 
water  ;  platinum  wire  melts  so  fast  that  it  runs  down  in 
drops  from  3  to  5  grains  in  weight !  Incombustible  sub- 
stances, such  as  flint,  crystal,  opal,  jaspis,  sapphire,  eme- 
rald, &/c,  are  almost  instantaneously  converted  into  a 
glassy  mass.  Gold  is  totally  vaporised  —  and  even  dia- 
monds, which  require  for  their  ignition  the  most  power- 
ful galvanic  batteries,  are  in  a  very  short  time  wholly 
evaporated,  when  exposed  to  the  burning  jet  of  the  com- 
pound blow-pipe.  In  short,  the  results  obtained  by  this 
apparatus  are  so  brilliant,  and  of  so  much  importance  to 
chemical  investigation,  that  it  must  be  classed  among  the 
most  important  and  beautiful  inventions,  that  have  been 
made  in  the  science  of  chemistry. 

§  22.  The  Blow-pipe  with  condensed  or y gen  and  hy- 
drogtn  gaseSj  although  not  an  original  invention  of  John 
Newman  (see  the  note  on  page  70,)  is  yet  a  highly  useful 
and  powerful  apparatus,  and  one  for  whose  improved  con- 
struction we  are  indebted  to  this  distinguished  philosopher. 


HYDROGEN. 


Fig.  LXXXV. 


It  consists  of  a  strong 
gas-holder,  A,  commonly 
made  of  copper,  which 
communicates  by  means 
of  a  turn-cock  E,  with  a 
strong  copper  barrel,  F, 
which  is  used  as  a  com- 
pression pump.  To  the 
'gas-holder,  A,  is  fitted  an 
extremely  narrow  pipe 
(about  three  inches  long, 
and  only  one  eighteenth  of 
an  inch  bore),  which,  in  H,  is  provided  with  a  discharging- 
cock.  The  compression  pump  F,  communicates  by  the 
turn-cock  G,  with  a  bladder  filled  with  inflammable  air  — 
(1  volume  of  hydrogen  mixed  with  two  volumes  of  oxygen, 
see  §  19). 

When  the  apparatus  is  to  be  used,  the  two  cocks,  E  and 
G,  are  opened,  and  the  piston  of  the  compression  pump 
moved  upwards.  <  By  this  means  the  air  from  the  bladder 
rushes  into  the  barrel  and  thence  into  the  gas-holder,  from 
which  the  atmospheric  air  must  previously  be  exhausted. 
The  cock  E  is  now  closed  and  the  piston  of  the  compres- 
sion pump  moved  down  to  compress  the  air  in  the  gas- 
holder. When  this  is  done,  the  cock  E  is  closed,  and  G 
opened,  when  by  raising  the  piston  another  portion  of 
inflammable  air  rushes  into  the  vacuum  created  in  the 
barrel,  which  by  a  fresh  stroke  downwards  is  again  forced 
into  the  gas-holder  ;  and  so  can  this  operation  be  contin- 
ued until  the  inflammable  air  in  the  gas-holder  is  suffi- 
ciently condensed  for  the  purpose  in  view.  The  cocks, 
E  and  G  are  now  closed,  and  the  dischavging-cock  open- 
ed, and  the  gas,  which  rushes  with  great  violence  through 
the  orifice  of  the  pipe  B  C,  ignited. 

The  effect  of  this  apparatus  on  various  substances  which 
have  been  submitted  to  the  heat  produced  by  the  burning  jet, 
is  in  every  respect  equal,  if  not  superior,  to  those  produced  by 
Hare's  oxy-hydrogen  blow-pipe  ;  but  the  apparatus  is  an  ex- 
ceedingly dangerous  one.  For  should  the  flame  at  the  mouth 
of  the  pipe,  C  D,  be  by  some  means  or  other  propagated  to  the 
gas-holder,  then  a  dreadful  explosion  would  take  place,  which 


HYDROGEN.  73 

would  shatter  the  whole  apparatus  into  fragments,  and  maybe 
connected  with  the  most  distressing  consequences  to  the  ex- 
perimenter. Prof.  Hare's  apparatus,  on  the  contrary,  is  per- 
fectly safe,  produces  nearly  the  same  effects,  and  may  be  made 
equally  powerful,  if  not  more  so,  by  providing  each  of  the  gas- 
holders with  a  compression  pump,  similar  to  that  employed  in 
Newman's  blow-pipe. 

Combination  of  Hydrogen  icith  Oxygen  —  Water. 

§  23.     EXPERIMENT.  —  Take  a  glass  bottle  filled  with  hydro- 
gen,  or  in  which  introduce  some  zinc, 
»•  kXXXVl.        with    a   proper   quantity  of  sulphuric 
acid  and  water  (as  in  experiment,  page 
65,  Fig.  LXXVIII);  ignite  the  hydro- 
gen which  is  then  evolved  at  the  mouth 
of  the  pipe,  and  conduct  it  into  a  bell- 
glass,  which,  instead  of  being  open  at 
the  bottom,  must  be  shaped  as  represen- 
ted in  the  adjoining  figure  (LXXXVI,) 
having   but  a  small   opening   for   the 
mouth  of  the  conducting  tube.     The 
product  of  the  combustion  will  be  the 
well-known  liquid   water,  which   will 
first  appear  as  vapor,  and  finally  run 
down  the  sides  of  the  glass,  and  collect 
in  small  quantities  in  the  cavities    at  the  bottom  of  the  bell- 
glass.     (Compare    the   experiment   described   page   G3,  Fig. 
LXXIV.) 

Query.  —  What  do  you  infer  from  this  experiment  ?  Jlns.  — 
That  the  water  is  a  compound  of  hydrogen  and  oxygen. 
Query  —  Why  ?  Jlns.  —  Because  it  is  formed  by  the  com- 
bustion of  hydrogen  :  and  every  combustion  is  a  combination 
of  oxygen  with  the  combustible  substance,  which  in  this  case 
is  the  hydrogen. 

§  24.  We  have  had  occasion  to  remark  before  that 
hydrogen  and  oxygen  are  evolved  by  the  decomposition  of 
water  (§  15)  ;  we  have  now  seen  that  water  is  re-produced 
from  hydrogen  and  oxygen.  It  remains  for  us  therefore 
only  to  ascertain  in  what  proportion  hydrogen  and  oxygen 
combine  to  water.  We  have  stated  in  the  Introduction, 
(page  11)  that  all  definite  compounds  are  formed  by  the 
combination  in  definite  proportions  of  their  elements  — 

7 


74 


HYDROGEN. 


and  we  have  already  observed  from  the  experiment  descri- 
bed on  page  60,  fig.  LXXI,  that  a  definite  proportion  of 
hydrogen  and  oxygen  is  obtained  from  the  decomposition 
of  water,  which  is  one  volume  of  oxygen  to  two  volumes 
of  hydrogen.  If  we  are  now  able  to  show  that  the  same 
proportion  (two  volumes  of  hydrogen  to  one  volume  of 
oxygen)  is  also  preserved  in  the  combination  of  these 
gases  to  water,  then  the  chemical  equivalent  of  water 
would  be  established  beyond  any  doubt  or  controversy. 
This  we  are  actually  enabled  to  show  by  the  following 

EXPERIMENT.  —  Procure  a  very  strong 
glass  tube,  abed,  fitted  to  a  brass  cap, 
cdcf,  and  provided  in  G  with  a  stop- 
cock. Two  small  holes  must  be  drilled 
in  the  upper  part  of  this  tube,  into  which 
two  small  wires,  M>,  w;,must  be  cemented 
in  such  a  manner  that  their  points  nearly 
touch  each  other  on  the  inside.  Provide 
a  mixture  of  pure  hydrogen  and  oxygen  in 
the  proportion  of  two  volumes  of  the 
former  to  one  volume  of  the  latter,  with 
which  fill  a  jar,  I,  fitted  with  a  stop-cock, 
PI,  to  which  the  cock  of  the  tube  may  be 
screwed,  in  a  manner  similar  to  Priest- 
ley's bell  glass  and  bladder  (Introduction, 
pages  30  and  31).  Extract  the  air  from 
the  tube  by  an  exhausting  syringe  or  an 
air-pump,  and  screw  it  tight  to  the  jar. 
When  the  two  cocks  are  opened  a  portion 
of  the  mixed  gases  will  rush  into  the 
tube  ;  this  it  is  best  to  extract  again  from 
the  tube  to  make  sure  of  the  exhaustion 
of  any  remaining  air.  Place  the  tube 

again  upon  the  jar,  and  by  opening  again 

both  cocks,  fill  it  another  time  with  the  mixture  of  the  gases  ; 
and  take  great  care  to  close  both  stop-cocks.  Now  pass  an 
electric  spark  through  the  wires,  and  the  gases  in  the  tube  will 
explode  (2  0,  page,  69).  Allow  the  tubes  to  cool;  after 
which  let  in  a  fresh  portion  of  the  mixture,  whicn,  when  the 
cocks  are  closed  may  again  be  inflamed  —  and  continue  this 
process  until  a  strong  dew  is  seen  upon  the  interior  of  the  tube 
This  upon  examination  you  will  find  to  be  pure  water. 

If  the  two  gases  are  mixed  in  the  exact  proportion  ot  two 


HYDROGEN.  75 

volumes  of  hydrogen  to  one  volume  of  oxygen,  then  the  whole 
mixture  will  be  consumed;  but  if  the  mixture  be  made  in 
any  other  proportion,  the  excess  of  either  gas  will  be  left; 
because  they  combine  in  no  other. 

Query— Why  must  the  glass  tube  in  this  experiment  be 
stronger  than  in  others  ?  Jlns.  —  Because  it  must  resist  the 
explosion  of  the  gases  when  an  electric  spark  is  applied  to 
them.  Query  —  Why  must  the  two  stop-cocks  be  carefully 
closed  before  the  electric  spark  is  passed  through  the  wire  ? 
Jlns.  —  Because  one  volume  of  oxygen  and  two  volumes  of  hy- 
drogen form  a  highly  explosive  mixture  (§  20,  page  69); 
consequently  if  the  cocks  were  not  closed  the  inflammation  of 
the  gases  in  the  tube  would  communicate  itself  to  the  jar,  and 
cause  an  explosion  which  would  destroy  the  jar,  and  endanger 
the  safety  of  the  experimenter.  Query  —  And  what  fact  does 
this  experiment  tend  to  establish  ?  Jlns.  —  It  establishes  the 
indisputable  fact  that  water  consists  of  two  volumes  of  hydrogen 
combined  with  one  volume  of  oxygen,  and  that  these  gases  com- 
bine in  no  other  proportion  to  water  than  in  that  of  two  vol- 
umes of  hydrogen  with  one  volume  of  oxygen, 

§  25.  The  law  which  we  have  just  found  respecting 
the  combination  of  hydrogen  and  oxygen  corroborates 
what  we  have  stated  in  the  Introduction  {page  11)  in  ref- 
erence to  the  composition  of  all  definite  compounds.  Now 
as  hydrogen  is  the  lightest  ponderable  substance  in  nature, 
it  will  combine  in  the  smallest  proportion  by  weight  with 
all  other  substances ;  consequently,  if  the  weight  of  hy- 
drogen which  combines  with  oxygen  is  taken  for  unity  of 
comparison,  the  chemical  equivalent  of  oxygen  is  8  ;  be- 
cause 1  volume  of  oxygen  weighs  8  times  as  much  as  the 
two  volumes  of  hydrogen  with  which  it  combines  ;  hydro- 
gen being  16  times  lighter  than  oxygen.*  But  the  chem- 
ical equivalent  of  oxygen  and  hydrogen  being  known,  that 
of  water  follows  of  course.  This  is  composed  of 
I  equivalent  of  hydrogen  equal  to  1 

and  1  equivalent  of  oxygen, equal  to  8 

consequently  chemical  equivalent  of  water  equal  to     9. 

*  Two  sixteenths  is  the  same  as  one  eighth  ;  consequently  the 
weight  of  the  two  volumes  of  hydrogen  is  only  one  eighth  of  the 
weight  of  one  volume  of  oxygen;  or,  which  is  the  same,  the  weight 
of  the  hydrogen  employed  is  to  that  of  the  oxygen  as  I  to  8. 


76  HYDROGEN. 

In  a  similar  manner  have  the  chemical  equivalents  of  oth- 
er substances  been  determined  in  reference  to  hydrogen  ; 
and  we  shall  make  it  a  rule  for  the  remainder  of  this  trea- 
tise, to  write  at  the  head  of  each  substance,  its  equiva- 
lent number  ;  and  if  the  body  we  treat  of  is  a  compound, 
then  we  shall  besides  this,  affix  the  chemical  equivalents 
of  its  elements. 

Some  philosophers  have  assumed  oxygen  as  the  standard 
of  comparison,  which  being  supposed  equal  to  100,  the  chem- 
ical equivalent  of  hydrogen  is  one  eighth  part  of  ICO,  or  12,5. 
Most  English  and  American  chemists  however  prefer  the  for- 
mer method,  on  which  account  we  have  adopted  it  throughout 
this  treatise. 

§  26.  The  composition  and  decomposition  of  gases 
follow  a  still  more  simple  law,  which  is  that  of  combining 
in  definite  volumes,  instead  of  definite  weights.  Thus,  when 
one  gas  combines  with  another,  1  volume  of  the  one, 
combines  always  with  1,  2,  3,  4,  &.c,  volumes  of  the  oth- 
er, and  in  no  intermediate  proportions. 

§  27.  Properties  of  water.  Water,  in  its  pure  state, 
is  destitute  of  color,  taste,  or  smell,  and  is  on  this  ac- 
count most  admirably  fit  to  be  the  natural  drink  of  man. 
It  is  the  most  universal  solvent  in  nature,  (dissolves  most 
solid  substances)  and  absorbs  many  of  the  gases,  such  as 
hydrogen,  oxygen,  nitrogen,  &c.  A  cubic  inch  of  dis- 
tilled (purified)  water  weighs  about  252  £  grains.  Its  great- 
est density  is  at  the  temperature  of  40  degrees  ;  it  freezes 
at  32°,  and  becomes  converted  into  stearn  at  the  tempera- 
ture of  212°  Fahrenheit.  According  to  the  nicest  exper- 
iments, it  is  composed  of  28Tf  <y  grains  of  hydrogen,  and 
224T436^  of  oxygen  ;  the  volume  of  hydrogen  is  1325  cubic 
inches,  and  that  of  oxygen  6(>2  ;  so  that  the  condensation 
of  these  gases  in  the  act  of  forming  water,  is  nearly  2000 
volumes  into  one ! 

Query  —  From  what  has  just  been  observed  respecting  the 
enormous  condensation  of  the  volumes  of  the  gases  which 
are  employed  in  the  formation  of  water,  can  you  now  account 
for  the  great  heat  given  off  during  the  cornhustion  of  hydro- 
gen? JJns. —  When  hydrogen  is  burnt  nearly  2CCO  volumes 
of  gas  (hydrogen  and  oxygen)  are  condensed  into  one  ;  by 


HYDROGEN.  77 

which  means  the  heat  which  was  hidden  in  the  gas  becomes 
sensible,  and  produces  the  astonishing  effects  of  the  compound 
blow-pipe,  and  the  explosive  mixture  of  hydrogen  and  oxygen. 

We  have  said  that  the  greatest  density  of  water  is  at  about 
40°  of  Fahrenheit's  thermometer.  In  this  respect  it  makes 
an  exception  to  all  other  liquids,  which  are  known  to  contract 
as  they  cool  down  to  their  freezing  points.  (Natural  Philoso- 
phy, Chap.  VI.)  This  peculiarity  of  water  is  of  the  greatest 
influence  upon  the  economy  of  nature.  The  water  which 
nearly  covers  one  third  of  the  earth,  becomes  a  most  efficient 
means  of  equalizing  its  temperature,  making  those  parts  hab- 
itable which  would  otherwise  be  buried  in  perpetual  frost,  or 
scorched  with  insufferable  heat.  The  cold  air  from  the  polar 
regions  absorbs  the  heat  from  the  great  waters  or  lakes  until 
they  are  cooled  down  to  40  degrees  Fahrenheit.  At  this  point 
the  refrigerating  influence  of  the  atmosphere  nearly  ceases ; 
because  the  uppermost  stratum  of  water,  by  further  cooling, 
becomes  lighter  (loses  its  density)  and  instead  of  sinking  to 
the  bottom,  remains  in  a  cake  of  ice  suspended  at  the  surface, 
preventing  thereby  the  water  below  from  being  further  expos- 
ed to  the  influence  of  the  colder  air.  Without,  this  peculiar 
property  of  water,  the  cold  air  would  continue  to  rob  it  of  its 
heat  until  the  whole  should  be  cooled  down  to  32  degrees, 
when  it  would  at  once  settle  into  a  solid  mass.  Every  living 
creature  in  it  would  perish  ;  the  ice  in  the  northern  regions 
would  never  be  liquefied,  and  navigation  finally  made  impossi- 
ble.* 

§  28.  Jce.  Water  in  the  act  of  freezing  or  congeal- 
ing (see  Natural  Philosophy,  Chap.  VI,)  expands  by 
nearly  J  of  its  volume,  and  so  great  and  violent  is  this 
expansion,  that  it  bursts  tubs,  casks,  water-pipes,  &c,  in 
which  water  is  suffered  to  freeze.  It  also  explains  why 
trees  and  plants  are  destroyed  in  hard  frosts,  and  such 
similar  phenomena.  The  specific  gravity  of  ice  is  less 
than  that  of  water,  viz,  only  T9^,  or  0.92,  that  of  water 
being  I.  This  is  the  reason  why  the  ice  remains  at  the 
surface  of  the  water,  and  explains  the  phenomena  alluded 
to  in  the  preceding  paragraph. 

*  Library  of  Useful  Knowledge,  treatise  on  Chemistry. 

7* 


78  HYDROGEN. 

§  29.  Rain,  River,  and  Pump-water.  We  distin- 
guish yet  between  Rain,  River,  and  Pump  water.  The 
purest  of  these  is  rain-water,  because  descending  through 
the  atmosphere,  it  is  least  exposed  to  the  influence  of  other 
substances.  JVext  to  it  comes  River  water,  which  however 
is  often  known  to  contain  certain  salts  of  soda,  lime,  and 
magnesia,  of  which  we  shall  speak  in  the  4th  Chapter. 
These  two  kinds  of  water  are  called  soft  water,  in  oppo- 
sition to  the  hard  pump-water,  which  contains  always  a 
greater  or  less  quantity  of  carbonic  acid.  Mineral  waters 
contain  gases  and  salts  in  such  proportions  that  they  are 
only  used  as  physics  in  medicine.  Sea  water  contains  a 
variety  of  salts.  Among  these  are  common  salt,  Glau- 
ber's salt,  muriate  of  lime  and  of  magnesia.  The  two 
last-mentioned  ingredients  give  it  that  disagreeable  taste 
and  smell,  which  causes  nausea  and  vomiting  when  taken 
into  the  stomach. 

§  30.  AH  kinds  of  water  contain  atmospheric  air 
(generally  from  3  to  4  per  cent),  not  indeed  as  a  chemical 
ingredient^  but  mechanically  mingled  with  their  particles. 
From  this  water  may  be  freed  either  by  the  air-pump, 
or  by  boiling.  The  latter  method  is  preferable. 

When  water  is  brought  under  the  receiver  of  an  air-pump 
and  the  air  is  exhausted  in  the  receiver,  the  particles  of  atmos- 
pheric air  which  are  mechanically  intangled  in  the  water,  rise  in 
little  bubbles  to  the  surface  and  expand  themselves  in  the  vacu- 
um created  over  the  water,  according  to  the  laws  of  elastic 
fluids  (Natural  Philosophy,  Chap.  IV).  The  boiling  of  water 
consists  in  heating  it  until  it  becomes  converted  into  steam. 
Just  before  this  takes  place  the  water  is  thrown  into  a  violent 
agitation,  partly  occasioned  by  the  expansion  of  the  atmospheric 
air  contained  in  it ;  little  bubbles  of  air  rise  to  the  surface  and 
escape  along  with  the  steam  which  is  forming  during  the  pro- 
cess of  ebullition. 

§31.  Water,  although  a  tolerably  good  conducter  of 
Electricity,  (Natural  Philosophy,  Chap.  VIII),  is  a  very 
bad  conductor  of  heat.  Of  this  we  can  easily  convince 
ourselves  by  the  following 


HYDROGEN.  79 

Fig.  LXXXVIII. 

EXPERIMENT.  — Place  a  small  air-thermometer 
capable  of  showing  very  minute  alteration  of  tem- 
perature, in  a  jar  filled  with  water,  so  that  the  bulb 
of  the  thermometer  may  be  a  little  below  the  sur- 
face. Upon  this  pour  a  small  quantity  of  ether, 
which  being  specifically  lighter  than  water,  will 
remain  on  top  and  may  be  inflamed.  The  ether 
will  burn  for  a  considerable  time  without  affecting 
the  thermometer  in  any  sensible  degree. 


It  will  indeed  be  quite  a  different  case  when  the  heat  is 
applied  to  the  water  from  below.  In  this  case  the  ther- 
mometer is  soon  affected.  But  then  it  is  not  the  conduct- 
ing power  of  water  which  transfers  the  heat  from  the  bot- 
tom of  the  jar  to  the  surface  and  the  thermometer ;  it  is 
because  the  heated  particles  of  water  themselves  are  ex- 
Fig,  LXXXIX. 

panded  and  rise  to  the  surface,  while  another  por- 
tion of  colder  water  sinks  from  the  surface  to  the 
bottom  and  occupies  their  place.  This  motion 
can  actually  be  observed  by  boiling  water  in  which 
some  particles  of  amber  or  of  some  other  light  sub- 
stance are  diffused,  in  a  glass  tube  applying  the 
heat  from  below.  The  particles  of  amber  will  be 
seen  to  rise  from  the  bottom  of  the  tube,  being  car- 
ried along  by  the  particles  of  water  to  which  they 
adhere,  while  those  near  the  surface  will  be  ob- 
served to  descend  with  the  colder  particles  of 
water.  The  same  experiment  may  be  made  with 
other  liquids,  all  of  them  being  bad  conducters  of 
heat,  and  capable  of  being  heated  only  in  conse- 
quence of  the  mobility  of  their  particles.  (See 
Natural  Philosophy,  Chap.  VI.) 
Query  —  Could  water  be  very  well  heated  without  the 
mobility  of  its  particles,  which  enables  those  which  are 
heated  to  ascend,  making  thereby  room  for  the  colder  ones  to 


80  HYDROGEN. 

descend  and  become  heated  ?  dns.  —  No  ;  because  the  con- 
ducting power  of  water  in  itself  is  very  bad,  as  we  have  seen 
from  the  experiment  described  in  Fig.  LXXXV1II.  Ques. — 
And  what  is  the  reason  that  the  burning  ether  on  the  surface 
of  the  water  in  that  experiment,  does  not  materially  affect  the 
thermometer?  Ans.  —  Because  the  heated  particles  on  the 
surface  of  water,  becoming  specifically  lighter,  must  of  course, 
from  hydrostatic  principles,  remain  on  top,  and  prevent  thereby 
the  next  lower  particles  from  ascending.  And  in  this  consists 
the  whole  difference  between  heating  a  liquid  from  below  and 
above  — (applying  the  heat  at  the  bottom  or  at  the  surface). 

§  32.  It  has  been  stated  in  Natural  Philosophy,  Chap. 
VI,  that  the  pressure  of  the  atmosphere,  or  of  steam,  is  an 
obstacle  to  the  boiling  of  liquids  and  consequently  also  to 
the  boiling  of  water.  This  has  been  stated  as  a  reason 
why  water  boils  sooner  under  the  receiver  of  an  air-pump, 
from  which  the  air  has  been  exhausted,  or  on  the  top  of 
high  mountains,  where  the  pressure  of  the  atmosphere  is  less 
than  on  the  plain,  &c  ;  but  we  can  illustrate  this  law  still 
more  strikingly  and  satisfactorily  by  the  following 

Fie   XC  EXPERIMENT  —  Adapt  a  cork  covered  with  a 

thick  coating  of  sealing  wax,  to  a  glass  flask, 
into  which  put  water  to  the  depth  of  about  one 
inch.  Place  it  over  a  lamp  until  it  boils,  and 
suffer  the  boiling  to  continue  for  a  short  time, 
after  which  introduce  the  cork  air-tight  and  re- 
move the  flask  from  the  lamp.  The  water  will 
boil  a  little  while  after  the  heat  ceases  to  be  ap- 
plied ;  but  on  plunging  the  flask  into  ajar  filled 
with  cold  water  or  ice,  the  boiling  recommences 
with  great  violence  and  continues  until  the  wa- 
ter in  the  flask  is  nearly  cold.  Jf  the  flask  is  ta- 
ken out  before  the  boiling  ceases,  and  is  plunged 
into  hot  water,  the  boiling  immediately  stops  ; 
but  upon  being  again  introduced  into  cold  water  the  boiling 
recommences  with  violence. 

Qutry.  —  Why  is  the  cork  in  this  experiment  introduced 
during  the  boiling  of  the  water  in  the  flask?  Ans.—  It  is 
done  in  order  to  exclude  the  atmospheric  air,  and  to  prevent 
the  escape  of  the  steam  with  which  the  flask  becomes  filled 
when  the  water  boils  in  it.  Ques.  —  Why  does  the  water  con 
tinue  to  boil  for  a  little  while  after  the  heat  ceases  to  be  ap- 


HYDROGEN. 


81 


plied  to  it?  Ans.  —  Because  when  the  flask  is  removed  from 
the  lamp,  its  sides  come  in  contact  with  the  cold  atmospheric 
air,  which  condenses  part  of  the  steam,  and  by  this  means 
lessens  the  pressure  on  the  surface  of  the  water  ;  this  enables  the 
water  to  boil  for  a  short  time,  although  its  temperature  is  re- 
duced. Qites. —  But  why  does  the  water  recommence  boiling 
when  the  flask  is  plunged  into  cold  water  or  ice  ?  Jlns.  —  Be- 
cause the  steam  in  the  flask  becomes  then  suddenly  conden- 
sed, removing  thereby  the  whole  pressure  from  the  water,  and  by 
that  means  throws  it  into  a  state  of  violent  ebullition.  Ques. — 
And  why  does  the  boiling  cease  when  the  flask  is  introduced 
into  hot  water  ?  JJns. — Because  this  leads  to  the  formation 
of  afresh  quantity  of  steam  in  the  flask,  whose  pressure  pre- 
vents the  boiling  of  the  water.  Qucs. —  And  what  inference 
should  you  draw  from  the  experiment  you  have  just  explained  ? 
Jlns.  —  That  water  (and  all  other  liquids)  require  higher  degrees 
of  temperature  to  boil  under  a  heavy  pressure  of  air  or  steam ; 
and  considerably  lower  degrees  of  temperature  to  boil  token  this 
pressure  is  removed  from  them. 

§  33.  Water  absorbs  constantly  a  portion  of  heat,  with 
which  it  either  combines,  or  through  the  medium  of 
which  it  becomes  converted  into  vapor.  The  quantities 
of  heat  or  caloric  thus  absorbed  by  the  large  waters  on 
our  globe,  tend  in  no  small  degree  to  moderate  the  tem- 
perature of  the  torrid  regions,  and  to  create  an  agreeable 
freshness  near  the  banks  of  rivers  and  on  the  seacoast. 
This  continued  formation  of  vapors  from  the  surface  of  wa- 
ter is  called  the  process  of  evaporation,  and  it  serves  some 
of  the  most  important  purposes  of  nature.  The  vapors  of 
water  contained  in  the  atmosphere  form  mists  or  clouds, 
which  when  brought  in  contact  with  the  higher,  and 
consequently  colder  strata  of  air,  are  condensed  and  de- 
scend again  as  dew,  rain,  or  snow,  to  moisten  our  fields  in 
summer,  or  to  protect  them  during  the  winter ;  assisting 
thereby  the  vegetation  of  trees  and  plants,  without  which 
animal  life  itself  would  soon  become  extinct.  (See  Natu- 
ral Philosophy,  Chap.  VI.) 

The  refrigerating  influence  of  forming  vapors  of  liquids  may 
be  illustrated  on  a  small  scale  by  the  following 


fcYDROGEN. 


Fig.  XCJ. 


EXPERIMENT.  —  Pro- 
vide a  watch-glass  filled 
with  water  and  place  it 
over  a  shallow  vessel  filled 
with  sulphuric  acid,  and 
bring  the  whole  under  the 
receiver  of  an  air-pump. 
As  the  air  is  exhausted 
from  the  receiver  vapors 
will  abundantly  rise  from 
the  water,  which  being 
speedily  absorbed  by  the 
sulphuric  acid  (which  has 
a  great  affinity  for  water) 
creates  such  a  degree  of 
cold  as  to  freeze  the  water 
in  a  very  short  time.  If 
instead  of  sulphuric  acid  we  employ  ether,  the  same  effect 
will  be  produced  ;  but  in  this  case  the  ether  becomes  vaporized, 
and  absorbs  such  a  quantity  of  heat  from  the  water  as  to  con- 
geal it. 

A  still  better  illustration  of  the  cold  produced  by  the 
rapid  process  of  evaporation  may  be  given  by  means  of 
an  instrument  invented  by  Dr  Wollaston,  and  which  has 
received  the  name  of  Cryophorus  or  Frust-bearcr. 

Fi<r   XCII.  It  consists  of  a  narrow 

glass  tube  of  from  18 
inches  to  2  feet  in  length, 
bent  towards  the  end  at 
right  angles  (see  Fig. 
XCII,)  and  terminating 
on  both  sides  in  bulbs.  One  of  these  bulbs  is  about  half 
filled  with  water  ;  this  being  made  to  boil  expels  the  at- 
mospheric air  from  the  tube  and  the  other  bulb  which  re-r 
mains  filled  with  steam.  The  open  bulb  is  then  closed  by 
means  of  a  blow-pipe  (see  Fig.  XXXIX,  page  26),  When 
the  empty  bulb  of  the  instrument  is  now  immersed  in  a 
mixture  of  salt  and  snow,  the  vapors  contained  in  it  are 
suddenly  condensed,  by  which  means  a  vacuum  is  created, 
which  removing  the  pressure  upon  the  surface  of  the  water 
in  the  other  bulb,  produces  such  a  rapid  evaporation 
as  to  freeze  the  water  in  it  although  at  a  distance  of  24 


HYDROGEN.  83 

inches  from  the   ice,  and  notwithstanding  the  slow  con- 
ducting power  of  water. 

The  effects  of  evaporation  are  also  happily  illustrated  in  the 
process  of  perspiration.  The  natural  temperature  of  the  human 
body  is  from  9fi  to  98  degrees  Fahrenheit ;  but  when  taking  ac- 
tive exercise,  or  exposed  to  a  fire,  or  the  heat  of  a  hot  summer's 
day,  this  temperature  would  naturally  be  heightened  to  a  de- 
gree which  would  be  injurious  to  health.  This,  however,  is  pre- 
vented by  the  appearance  of  a  watery  fluid  on  the  skin,  which 
by  its  evaporation  exercises  a  cooling  effect  on  the  body  and 
reduces  it  to  its  healthy  temperature. 

Query  —  But  why  is  it  dangerous  to  be  exposed  to  a  current 
of  cold  air  after  the  clothes  have  become  moist  with  perspira- 
tion ?  Jlns.  —  Because  the  rapid  process  of  evaporation  may 
then  reduce  the  temperature  of  the  body  to  a  degree  which 
may  be  equally  injurious  to  health. 

§  34.     Disli/latinn  of  water.     In  order  to  obtain  water 
in  its  pure  state  it  is  necessary  to  distill  it.     For  this  pur- 
pose we  make    use  of  a  common   still  (see  Fig.  XXVI, 
Fig.  XCIII. 


page  22).  Small  quantities  may  be  obtained  by  heating 
water  in  a  flask  A,  over  an  Argand's  lamp,  and  convey- 
ing the  steam  which  is  formed,  through  a  pipe,  P,  fitted 
air-tight  to  the  neck  of  the  flask,  into  a  receiver  C,  which 
for  thU  purpose  must  be  surrounded  by  water  or  other 
means  of  reducing  its  temperature.  The  steam  formed 
by  the  boiling  of  the  water  in  the  flask  is,  in  the  receiver, 
again  condensed,  and  descends  as  liquid  water  through 
the  discharging  cock,  D,  where  it  may  be  collected  in  a 


84  HYDROGEN. 

vessel.  The  water  thus  obtained  is  free  from  all  impuri- 
ties, salts,  &c,  which  remain  at  the  bottom  of  the  flask 
A,  after  the  water  has  been  converted  into  steam,  and  is 
used  for  chemical  and  medicinal  purposes. 

§  35.  We  have  learned  in  Natural  Philosophy  (Chap. 
VI),  that  when  water  boils  it  ceases  to  assume  a  higher 
degree  of  temperature  ;  all  the  heat  further  added  becom- 
ing then  hidden  or  employed  in  the  formation  of  steam. 
But  if  the  vessel  is  closed  in  such  a  manner  as  to  prevent 
the  steam  from  passing  off,  then  the  steam  may  be  heated 
to  a  much  higher  degree,  and  being  concentrated  in  a 
small  space  Is  capable  of  exercising  an  immense  pressure 
This  is  taken  advantage  of  in  the  construction  of  steam 
engines.  Water  may  in  this  manner  be  expanded  to  near- 
ly 1700  times  its  volume  ;  1  cubic  inch  of  water  giving 
nearly  1  cubic  foot  (1728  cubic  inches)  of  steam. 

The  principal  properties  of  steam  may  be  exhibited  by 
the  following 

Fig.  XCIV.  EXPERIMENT.  —  Provide  a  glass  tube  of  about 
three  fourths  of  an  inch  bore,  and  from  7  to  8 
inches  long.  Close  it  at  one  end.  and  enlarge 
it  a  little  by  blowing  into  it  when  softened  by 
the  heat  of  a  blow-pipe  (see  Introduction,  Fig. 
XXXVIII,  page  26).  Take  a  wooden  rod  about 
10  inches  long,  and  wrap  apiece  of  wash-leath- 
er about  one  end  of  it,  just  enough  to  form  a 
piston  which  will  move  freely  up  and  down  in 
the  tube.  The  glass  tube  may  be  passed 
through  a  piece  of  cork  wood,  into  which  a  fork 
or  some  other  sharp  instrument  may  be  stuck 
for  a  handle,  to  hold  the  whole  apparatus  over 
the  flarnc  of  a  lamp.  The  piston  must  not  be 
introduced  in  the  tube  until  the  air  is  expelled 
from  it,  by  the  boiling  for  some  time  of  the  wa- 
ter. The  remainder  of  the  tube  being  now  fill- 
ed with  steam,  introduce  the  piston  a  little  way, 
and  plunge  the  tube  into  water.  The  piston  will 
instantly  be  driven  down  ;  but  by  holding  the 
tube  again  over  the  flame  of  the  lamp,  the  piston 
is  again  driven  upwards,  and  so  may  the  piston 
be  alternately  driven  upwards  and  downwards 
by  repeatedly  heating  and  cooling  the  water 
in  the  bulb  of  the  tube. 


HYDROGEN.  85 

Query  —  Why  is  the  piston  in  this  experiment  driven  down 
when  the  tube  is  plunged  into  cold  water?  rfns.  —  Because 
by  plunging  the  tube  into  cold  water  the  steam  is  suddenly 
condensed  and  a  vacuum  created,  into  which  the  piston  is  forced 
by  the  pressure  of  the  atmosphere.  Ques.  —  But  why  is  the 
piston  moved  up  again  when  the  bulb  of  the  tube  is  again  held 
over  the  flame  of  the  lamp  ?  ~4ns.  — Because  the  water  in 
the  bulb  resuming  the  process  of  boiling,  is  again  converted 
into  steam  which  expands  itself  in  the  tube  and  forces  the 
piston  upwards.  Ques.  —  What  then  is  the  principal  cause  of 
the  prodigious  power  of  the  steam-engine  ?  Jlns.  —  The  pro- 
duction and  sudden  annihilation  of  the  steam  formed  in  the 
boiler.  (For  the  description  of  the  steam  engine,  see  the  Ap*- 
pendix). 

With  regard  to  the  other  applications  of  water  to  the  pur- 
poses of  common  life,  we  can  only  say  that  they  are  innu- 
merable, as  there  is  none  of  the  arts  which  can  dispense 
with  it,  and  its  presence  is  absolutely  indispensable  to  the 
continuance  of  all  animal  and  vegetable  life  on  our  globe. 

§  36.  Modes  of  ascertaining  the  purity  of  water. 
Pure  water  being  a  great  object  to  the  physician,  the 
chemist,  and  the  manufacturer,  it  may  perhaps  be  desira- 
ble to  acquaint  ourselves  with  some  of  the  means  of  as- 
certaining its  purity.  Chemically  pure  water  must 

1.  Not  redden  Litmus  paper,  —  otherwise   it  is  a  sign 
of  its  containing  an  acid  ; 

2.  It  must  not  form  a  precipitate  when  mixed  with  a 
solution  of  acetate  of  lead  ;  for  in  this  case  it  would  con- 
tain sulphuric  acid  ; 

3.  Mixed  with  lime-water  it  must  not  become  turbid; 
otherwise  it  would  contain  carbonic  acid. 

4.  With  a  solution  of  potash   it  must  not  form  a  pre- 
cipitate, because  in  this  case  it  would  contain  earthy  salts. 
(See  Chap.  IV,  Introd.  to  salts.) 

5.  It  must  not  become  turbid  with  a  solution  of  Prus- 
siate  of  iron   and  potash ;  otherwise  it  contains  metallic 
salts,  and  especially   iron,  if  the  precipitate  is  blue,  and 
copper  if  the  precipitate  is  brown. 

In  many  cases   it  is  only  necessary  to.  know  what  pro- 
portion the   solid   substances  mechanically  contained  or 
8 


86  HYDROGEN. 

entangled  in  the  particles  of  water,  bear  to  the  whole 
volume  of  the  liquid.  For  this  purpose  it  is  sufficient  to 
suffer  a  measured  quantity  of  water  to  evaporate  slowly 
over  a  moderate  fire,  or  from  an  evaporating  dish  made 
of  porcelain  (see  Fig.  XXIV,  page  21)  and  bedded  in 
sand.  The  dry  residue,  which  is  generally  of  a  white 
color,  may  then  be  weighed  and  compared  to  the  volume 
of  water. 

Deutoxide  of  Hydrogen  —  or  Oxygenized   water. 

Composition  :     1  equivalent  of  hydrogen  =    1 
2  equivalents    of   oxygen  =  16 

Chemical  equivalent  of  oxyg.  water  =  17. 

§  37.  Water  was  for  a  long  time  supposed  to  be  the 
only  compound  of  hydrogen  and  oxygen.  Another  combi- 
nation of  the  same  elements  has,  however,  been  recently 
discovered,  which  consists  of  equal  volumes  of  hydrogen 
and  oxygen  (water  being  a  combination  of  2  volumes  of 
hydrogen  with  1  volume  of  oxygen).  It  is  obtained  by  an 
exceedingly  tedious  and  expensive  process,  from  a  sub- 
stance called  Deutoxide  of  Barytium,  but  is  nevertheless 
used  in  Paris  for  divers  processes  in  bleaching  cambric 
and  calicos.  It  was  discovered  by  Thenard,  a  celebra- 
ted French  Chemist,  and  consists,  as  we  have  stated,  of 

2    volumes  of  hydrogen  =     I 
2  volumes  of  oxygen  (each  =  8)  =  16 

consequently  its  chemical   equivalent  is     17. 

§  38.  Properties  of  oxygenized  water It  is  a  color- 
less liquid,  of  a  metallic  bitter  taste,  a  highly  disagreeable 
nauseous  smell,  bleaches  and  dries  the  skin,  destroys  all 
vegetable  colors  (on  which  account  it  is  used  in  bleaching) 
and  may  be  mixed  with  water  in  all  proportions  without 
being  decomposed. 

Metals  brought  in  contact  with  it  are  speedily  oxidized  : 
but  silver  and  platinum  thrown  into  it  cause  an  explosion, 
without  suffering  any  visible  change  or  oxidation  —  a  phe- 
nomenon which  has  not  as  yet  been  satisfactorily  ex- 
plained. 


NITROGEN.  87 

Recapitulation  of  the  Binary  Comb' nations  of  Hydrogen 
and  Oxygen. 

/•  water,  or  protoxide    of 
^  hydrogen, 
Hydrogen  combines  with  oxygen  to 


J    Oxygenized  water,   or 
V.  deutoxide  of  hydrogen. 


C.     Nitrogen,  or  Azote. 

Chemical   equivalent  =  14. 

§  39.  This  is  an  inodorous  gas,  which  is  destitute  of 
color  or  taste,  and  constitutes  about  79  per  cent  of  the 
whole  weight  of  our  atmosphere.  It  is  but  sparingly  ab- 
sorbed by  water,  enters  largely  into  the  composition  of  all 
animal  substances,  but  is  of  itself  incapable  to  support 
animal  life.  It  is  not  inflammable  and  extinguishes  all 
burning  bodies  the  moment  they  are  introduced  into  it. 
When  separated  from  its  combination  with  oxygen  by  the 
influence  of  galvanic  electricity,  it  adheres  to  the  negative 
pole,  wherefore  it  is  called  a  positively  electric  substance. 
(See  introduction,  page  41.) 

This  gas  has  formerly  been  called  azote,  from  a  Greek  word 
signifying  destroyer  of  life.  This  expression  however  is  not 
correct,  for  the  gas  is  no  poison  —  it  is  merely  incapable  of 
support  ing  life,  or  the  process  of  respiration  without  the  pres- 
ence of  oxygen.  It  is  nevertheless  taken  into  the  lungs,  as 
we  shall  see  hereafter,  and  is  probably  destined  to  reduce  the 
injurious  effects  which  would  be  produced  by  the  respiration 
of  pure  oxygen. 

§  40.  Mode  of  obtaining  Nitrogen.  Nitrogen  is  prin- 
cipally and  easiest  obtained,  by  separating  it  from  atmos- 
pheric air.  This  is  done  by  burning  phosphorus  under  a 
bell-glass  or  receiver  (see  Fig  LXV,  page  54).  During 
the  combustion  the  oxygen  of  the  air  in  the  bell-glass  com- 
bines with  the  phosphorus  to  phosphoric  acid,  which  is 
rapidly  absorbed  by  the  water  over  which  the  glass  must 
be  placed.  The  residue  of  air,  after  all  the  oxygen  is 
consumed  by  the  process  of  combustion,  is  nitrogen,  which 


88  NITROGEN. 

may  be  collected  by  means  of  a  pneumatic  tub,  an  appa- 
ratus already  frequently  described  in  the  preceding  sec- 
tions (see  Introduction,  Fig.  XL1X,  page  30).  Nitrogen 
may  also  be  obtained  from  a  variety  of  animal  substances 
particularly  from  meat,  as  we  shall  see  in  the  7th  Chapter. 

Mixture  of  Nitrogen  with  Oxygen  —  Atmospheric  Air. 

§  41.  Nitrogen  and  oxygen  may  be  mixed  in  all  pro- 
portions, but  four  volumes  of  nitrogen  with  one  volume  of 
oxygen  form  a  mixture  resembling  in  all  essential  proper- 
ties our  atmospheric  air. 

That  nitrogen  and  oxygen  are  actually  contained  in  the  at- 
mosphere in  the  proportion  of  4  volumes  of  the  former  with  1 
volume  of  the  latter,  is  evident  from  the  fact,  that  when  a 
candle  is  burnt  under  a  receiver  provided  with  a  scale  to  indi- 
cate the  diminution  of  air  during  the  process  of  combustion, 
one  fifth  of  the  whole  volume  of  air  is  always  consumed  by 
the  loss  of  oxygen,  which  agrees  perfectly  with  the  state- 
ment we  have  just  made.*  This  experiment  has  already  been 
described  in  Fig.  LXVI1,  page  56. 

§  42.  Atmospheric  air.  The  atmosphere  of  the  globe, 
whose  mechanical  properties  have  already  been  described 
in  .Natural  Philosophy  (Chap.  V),  contains  in  addition  to 
nitrogen  and  oxygen  which  form  its  principal  ingredients, 
a  greater  or  less  portion  of  vapors  of  water  and  carbonic 
acid  gas —  a  substance  with  whose  properties  we  shall  be- 
come acquainted  in  the  next  chapter.  The  quantity  of  va- 
por is  continually  varying,  and  depends  upon  the  tempera- 
ture and  situation  of  the  place,  whether  it  is  in  the  neigh- 
borhood of  large  basins  of  water  —  or  removed  from  thesea« 
coast  and  the  shores  of  rivers —  upon  the  season  of  the  year, 
and  upon  the  particular  hour  of  the  day.  We  know  that 
in  the  spring  and  fall  of  the  year  the  atmosphere  is  more 
damp  than  in  summer  or  winter  ;  and  that  the  morn- 
ings and  evenings  are  generally  misty  or  foggy  during 
those  seasons.  As  regards  the  proportion  of  carbonic 

*  If  4  volumes  of  nitrogen  and  1  volume  of  oxygen  constitute  at- 
mospheric air,  then  the  oxygen  must  be  one  fifth  of  the  whole 
volume. 


NITROGEN.  89 

acid  gas,  it  is  greater  in  summer  than  in  winter,  and  dur- 
ing the  night  than  in  day-time. 

If  we  abstract  for  a  moment  from  the  variable  portion  of 
vapor  of  water  contained  in  our  atmosphere,  we  may  suppose 
it  to  be  composed  as  follows: 

21  per  cent  oxygen, 

78f$j9(jdo.    nitrogen, 

ToVo  d°-  of  carbonic  acid  gas. 

§  43.  The  proportion  of  the  principal  ingredients  of 
our  atmosphere,  nitrogen  and  oxygen,  is  invariably  the 
same,  viz:  21  weights  of  oxygen  to  79  weights  of  nitro- 
gen, whether  we  examine  the  air  on  top  of  the  highest 
mountains,  or  at  the  level  of  the  sea,  under  the  equator  or 
in  the  polar  region,  in  winter  or  in  summer. 

Gay  Lussac,  a  celebrated  French  chemist,  found  no  percep- 
tible difference  with  regard  to  this  ratio  (21  weights  of  oxygen 
to  79  of  nitrogen)  between  the  air  at  the  height  of  24,600  feet 
above  the  level  of  the  sea,  and  that  of  the  most  crowded  thea- 
tre in  Paris.  What  is  most  wonderful  and  inexplicable  in  this 
ratio,  is  its  permanency,  notwithstanding  the  prodigious  con- 
sumption of  oxygen  during  combustion  and  in  the  various 
processes  of  animal  and  vegetable  life. 

Many  trials  have  been  made  to  see  whether  no  other  mix- 
ture of  gases  can  support  respiration  and  animal  life  as  well 
as  our  atmosphere  ;  but  none  has  succeeded.  If  the  proportion 
of  its  mixture  were  changed,  by  an  addition  of  nitrogen  or  a 
diminution  of  oxygen,  it  is  highly  probable  all  animal  and 
vegetable  life  would  cease  ;  while,  on  the  contrary,  by  an  addi- 
tional quantity  of  oxygen  or  a  diminution  of  nitrogen,  all  vital 
energies,  and  consequently  life  itself  would  be  exhausted  too 
rapidly. 

§  44.  Accidental  ingredients  of  our  atmosphere.  Be- 
sides the  gases  already  enumerated,  our  atmosphere  con- 
tains at  different  times  and  places,  a  variety  of  other  sub- 
stances—  such,  as  carluretted  hydrogen,  in  marshy  coun- 
tries and  in  the  vicinity  of  coal  mines ;  sulphuretted 
hydrogen,  in  the  neighborhood  of  sulphur  baths  ;  sulphu- 
ric acid  gas  in  the  immediate  vicinity  and  at  the  craters 
of  volcanoes,  &c. 

All  bodies  on  our  globe  are  continually  exposed  to  the  in- 
fluence of  the  atmosphere.  Most  chemical  phenomena  take 


90 


NITROGEN. 


place  in  it.  The  processes  of  respiration,  combustion,  fermen- 
tation, and  putrefaction  (see  Chap.  VII,  on  the  spontaneous 
decomposition  of  vegetable  matter),  are  instances  of  its  con- 
tinual operation  upon  all  animate  and  inanimate  nature.  It 
has  therefore  become  a  matter  of  great  importance  to  find 
means  of  ascertaining  its  chemical  composition  at  various  times 
and  places,  and  so  much  has  this  become  a  subject  of  chemical 
speculation  that  some  chemists  treat  of  it  as  a  separate  branch 
of  the  science,  which  they  call  Eudiometry,  signifying  measure 
of  the  quality  of  the  atmosphere.  We  shall  now  proceed  to 
describe  some  of  the  apparatus  used  or  suggested  for  this 
purpose. 

§  45.  The  object  of  Eudiometry  in  most  cases  is  to 
ascertain  the  quantity  of  nitrogen  or  oxygen  contained  in 
the  atmosphere.  Any  substance  which  will  absorb  or 
consume  all  the  oxygen  from  a  confined  portion  of  air,  will 
serve  this  purpose,  provided  this  substance  does  not  itself 
mix  with,  or  alter  the  volume  of  the  nitrogen.  An  appa- 
ratus constructed  for  this  purpose  is  called  a  Eudiometer. 
A  great  variety  of  them  have  been  suggested,  but  the  fol- 
lowing three  are  the  most  useful,  and  commonly  employed 
by  practical  chemists. 

1.  AcharcTs  Eudiometer  by  the  slow 
combustion  of  phosphorus.  It  consists  of 
a  glass  tube  (see  Fig.  XCV),  closed  at 
one  end  6,  where  it  is  blown  into  a  bulb 
c.  In  this  small  sticks  of  phosphorus 
are  to  be  placed,  about  one  third  grain  to 
one  cubic  inch  of  atmospheric  air  ;  the 
remainder  of  the  tube  is  then  filled  with 
quicksilver,  and  with  its  open  end  down- 
wards, placed  into  a  jar  filled  with  the 
same  metal.  Atmospheric  air  is  now 
allowed  to  pass  through  the  pneumatic 
apparatus  into  the  tube  (quicksilver  being 
throughout  employed  instead  of  water), 
and  The  oxidation  of  the  phosphorus, 
which  has  a  great  affinity  for  oxygen,  increased  by  heat- 
ing the  bulb  c,  by  the  flame  of  a  candle.  The  oxygen  of 
the  atmospheric  air  in  the  tube  will  unite  with  the  phos- 
phorus, leaving  a  residue  of  nitrogen  in  the  gradated  tube 
a  b,  from  which,  and  the  whole  volume  of  atmospheric  air 


Fig.  XCV. 


NITROGEN.  91 

employed  in  the  experiment,  we  are  able  to  judge  of  the 
quantity  of  oxygen  consumed  ;  or,  which  is  the  same,  of 
the  proportion  in  which  oxygen  entered  in  the  composi- 
tion of  the  atmospheric  air  employed  in  the  experiment. 
Thus,  if  one  fifth  of  the  whole  volume  of  atmospheric  air 
should  combine  with  the  phosphorus,  the  remaining  nitro- 
gen would  be  four  fifths  of  the  whole  volume  employed  ; 
consequently  the  proportion  of  oxygen  to  nitrogen  would 
be  as  1  to  4. 

Fig.  XCVI. 

2.  The  Eudiometer  by  detonating  Oxygen  and 
Hydrogen  gas  (see  Fig.  XCVt)  is  an  invention  of 
Volta,  and  is  founded  on  the  principle  that  one 
volume  of  oxygen  combines  with  two  volumes  of 
hydrogen  to  water  (see  §  15,  page  61).  It  con- 
sists of  a  strong  glass  tube  a,  (see  the  figure)  fitted 
at  one  end  to  a  brass  box,  which  terminates  on  the 
outside  in  a  knob  c,  of  the  same  metal,  and  is  con- 
nected with  a  piece  of  bent  wire  in  the  tube. 
When  the  apparatus  is  to  be  used,  the  tube  is  fill- 
ed with  a  mixture  of  two  volumes  of  hydrogen  and 
one  volume  of  atmospheric  air,  (which  is  easily  done  by 
means  of  the  pneumatic  tub)  and  an  electric  spark  ap- 
plied to  the  knob  c.  The  mixture  of  the  gases  in  the  tube 
will  explode  (§  20,  page  69)  and  the  hydrogen  combine 
-with  the  oxygen  of  the  atmospheric  air  to  water  ;  the 
quicksilver  or  water  of  the  pneumatic  tub,  over  which  the 
experiment  must  be  made,  will  instantly  rise  in  the  tube 
and  show  the  volume  of  gas  consumed  ;  one  third  of 
which  is  always  the  oxygen  contained  in  the  atmospheric 
air  examined. 

Instead  of  the  Eudiometer  just  described,  we  may  use  the 
apparatus  Fig.  LXXXVIT,  page  74.  The  experiment  is 
nearly  the  same  as  that  described  on  that  page,  with  the 
only  difference,  that  atmospheric  air  is  employed  instead 
of  the  oxygen. 

Qwer?/  —  I5y  what  means,  in  the  last  experiment,  are  you 
able  to  find  the  volume  of  oxygen  contained  in  the  atmospher- 
ic air.  Ans.  —  By  the  combustion  of  the  hydrogen,  which, 
with  the  oxygen  of  the  atmospheric  air  combines  to  water. 


92  NITROGEN. 

Ques.  —  But  what  reason  have  you  to  infer  that  exactly  one 
third  of  the  whole  volume  of  gases  consumed,  is  the  quantity 
of  oxygen  which  was  contained  in  the  atmospheric  air? 
jjns. —  Because  two  volumes  of  hydrogen  combine  with  ex- 
actly one  volume  of  oxygen  to  water,  consequently  of  the 
three  volumes  consumed,  the  oxygen  constitutes  necessarily 
one  third. 

Fig.  XCVII. 

Gay  Lussac's  Eudiometer,  which  we  are  now 
about  to  describe,  is  founded  on  the  property  of 
some  liquids  to  absorb  certain  gases,  contained  at 
different  times  and  places  in  our  atmosphere.  It 
consists  of  a  cylindrical  jar,  which  is  fitted  to  a 
brass  box,  terminating  in  a  neck,  shaped  like 
that  of  a  bottle,  and  provided  with  a  cork,  through 
which  a  gradated  tube  may  be  made  to  com- 
municate with  the  jar.  When  the  apparatus  is 
to  be  used  the  gradated  tube  is  first  filled  with 
air,  and  then  fitted  to  the  jar,  which  must  be 
filled  with  such  liquids  as  are  capable  to  absorb 
the  gases  which  we  suppose  to  be  contained  in 
the  atmospheric  air  under  examination.  The 
whole  apparatus  is  then  inverted  for  some  time,  so  that 
the  air  from  the  tube  may  ascend  into  the  jar  —  and  after- 
wards, in  its  proper  position,  placed  under  water  or  quick- 
silver ;  the  rise  of  the  liquid  in  the  tube  will  indicate  the 
quantity  of  gas  absorbed,  and  thereby  enable  us  to  judge 
of  the  ingredients  contained  in  the  atmosphere. 

The  various  experiments  which  have  been  made  with  these 
Eudiometers  have  convinced  us  that  the  oxygen  contained  in 
the  atmosphere  is  absolutely  invariable,  at  all  times  of  the  day 
and  year.  The  great  difference  therefore  which  exists  between 
the  air  of  certain  places,  and  the  great  influence  which  the 
atmosphere,  at  different  times,  has  upon  our  state  of  health, 
cannot  be  explained  from  the  greater  or  less  quantity  of  oxygen 
which  it  contains,  but  is  owing  to  certain  principles  which  it 
is  impossible  for  us  to  determine  with  any  degree  of  precision. 
The  different  miasmas  which  at  times  are  contained  in  the  at- 
mosphere, and  are  supposed  to  be  the  cause  of  the  existence 
or  spreading  of  contagious  diseases,  escape  likewise  wholly 
our  observations  ;  their  nature  being  entirely  different  from 
any  known  element  in  chemistry. 


NITROGEN.  93 

Combinations  of  Nitrogen  with  Oxygen. 

§  46.  Nitrogen  combines  with  oxygen  in  five  different 
proportions,  forming  with  it  2  oxides  and  3  acids.  (See  the 
nomenclature  of  oxides  and  acids,  §  4,  page  51.)  Their 
names,  according  to  their  composition,  are  Protoxide  of 
nitrogen,  Deutoxide  of  nitrogen,  or  nitric  oxide,  hypo- 
nitrous  acid,  nitrous  acid,  and  nitric  acid. 

Protoxide  of  Nitrogen. 

Chemical  Composition. :     \   Equiv.  Nitrogen  =  14 
1       do.      Oxygen  =    8 


Chemical  equiv.  of  Protoxide  of  Nitrogen  =  22. 

§  47.  Protoxide  of  nitrogen' is  never  found  in  its  sim- 
ple state.  It  is  altogether  a  product  of  art,  and  is  best  ob- 
tained by  the  following 

Fig.  XCVIII.  EXPERIMENT.  —  Fuse  a  salt  called  JVr- 

trate  of  ammonia  in  a  retort  over  an  Ar- 
gand's  or  spirit  lamp  ;  or  as  this  salt  is  not 
always  readily  obtained,  prepare  it  from 
a  solution  of  carbonate  of  ammonia  (the 
principal  ingredient  of  common  smelling 
salts)  in  diluted  nitric  acid.  Evaporate  the 
solution  until  its  consistency  is  such  that  a 
drop  taken  out  with  a  glass  rod  concretes 
on  cooling.  When  this  is  done,  liquefy 
the  salt  thus  obtained,  and  keep  it  simmering  by  a  gentle  heat. 
The  gas  will  be  given  off  in  abundance,  and  may  be  collected 
by  the  pneumatic  tub.  For  this  purpose  however  it  is  neces- 
sary to  conduct  the  pipe  to  the  top  of  the  receiver,  as  is  shown 
in  the  figure  ;  because  the  "as  has  a  strong  affinity  for  water, 
and  would  otherwise  be  absorbed  by  it  in  a  great  proportion. 

§  48.  Properties  of  Protoxide,  of  Nitrogen,  The 
Protoxide  of  nitrogen  is  a  coloiless  gas  of  a  sweetish  taste, 
and  faint,  agreeable  smell.  It  becomes  liquid  by  pressure  : 
is  not  inflammable,  but  supports  combustion  with  more 
splendor  than  common  atmospheric  air.  Animals  die  in 
it  speedily.  When  breathed  in  small  quantities  it  pro- 
duces an  exhilarating  effect,  similar  to  that  produced  by 
spirituous  liquors.  It  mostly  occasions  an  irresistible 


94  NITROGEN. 

propensity  to  laughter  and  muscular  exertion  ;  but  taken 
in  greater  quantities  produces  swoon  and  apoplexy. 

For  the  purpose  of  taking  this  gas  into  the  lungs,  we  may 
take  Priestley's  bell-glass  instead  of  a  receiver,  and  transfer 
the  gas  which  is  collected  in  it  to  a  bladder,  from  which  it  may 
be  breathed.  Sir  Humphry  Davy  is  said  to  have  inhaled  12 
quarts  of  this  gas.  But  this  is  rather  a  dangerous  experiment ; 
the  greatest  quantity  of  it  inhaled  at  any  one  time  ought  not 
to  exceed  3  or  4  quarts,  and  even  these  are  known  to  have 
produced  the  most  distressing  consequences  on  the  particular 
constitution  of  individuals. 

Protoxide  of  nitrogen  may  by  electricity  be  again  decom- 
posed into  its  elements,  nitrogen  and  oxygen.  When  mix- 
ed with  hydrogen  it  becomes  inflammable,  and  on  the  ap- 
plication of  an  electric  spark  detonates  with  great  violence. 

Its  composition  by  volumes  is  one  volume  of  nitrogen 
with  one  volume  of  oxygen.  Its  chemical  proportion  or 
equivalent  by  weights  have  been  stated  in  the  introduction. 

It  will  however  be  well  to  say  here  a  few  words  on  the  mode 
of  reasoning,  or  the  species  of  chemical  analysis  by  which 
the  equivalents  of  this  gas  have  been  determined.  Two  vol- 
umes of  hydrogen  have  been  mixed  with  two  volumes  of  Pro- 
toxide of  nitrogen,  and  detonated  by  means  of  an  electric 
spark  in  the  apparatus  described  on  fig.  LXXXVII,  page  74. 
By  this  means  the  protoxide  of  nitrogen  has  become  completely 
neutralized,  its  oxygen  combining  with  the  hydrogen  to  water, 
and  the  residue  being  exactly  two  volumes  of  nitrogen. 

But  we  know  that  two  volumes  of  hydrogen  can  neutralize 
neither  more  nor  less  than  one  volume  of  oxygen,  we  infer 
therefore  that  in  protoxide  of  nitrogen  there  could  not  be  ei- 
ther more  or  less  than  one  volume  of  oxygen,  combined  with 
two  volumes  of  nitrogen.  If  now  we  wished  to  determine  the 
proportion  in  which  these  substances  are  combined  by  weight, 
it  would  only  be  necessary  to  know  the  weight  of  a  given  vol- 
ume of  both  gases. 

Taking  therefore  any  given  volume,  say  50  cubic  inches,  for 
the  standard  of  comparison,  we  say, 

50  cubic  inches  of  oxygen  weigh  16.8  grains 

double  this  volume,  or  100  cubic  inches  of  nitrogen  weigh  20.7* 

*  This  has  been  found  by  experiment;  or  the  weight  of  50  cubic 
inches  of  either  gas  may  also  be  calculated  from  its  specific  gravity 
wben  compared  to  the  weight  of  a  cubic  inch  of  water  (see  §  27, 
page  76.) 


NITROGEN.  95 

consequently  the  chemical  equivalent,  or  proportion  by  weight 
of  nitrogen,  is  to  the  chemical  equivalent  of  oxygen  (which  we 
know  is  8  —  see  page  75)  as  29.7  is  to  16.8  —  or  which  is  the 
same,  we  have  the  proportion. 

16.8     :    29.7  ;;      8     :     Answer  =  14,  nearly ;  which 
29.7  is  therefore  the  chemical  equiv- 
g  olent  of  nitrogen,  or  the  proper- 
ly aW:>7  *YIQQ  tion   in   which  it  combines  by 
16.8^37.6(13.9  weight  withall  Qther  substan. 

ces. 

656 

504 


15^0 
1512 


Now  knowing  the  chemical  equivalent  of  nitrogen  and  also 
that  of  the  oxygen,  with  which  it  combines  to  protoxide  of 
nitrogen,  it  is  only  required  to  add  them  together  to  obtain  the 
chemical  equivalent  of  that  substance,  viz. 

2  volumes  or  1  equivalent  of  nitrogen  =  14 
and  1  volume  or  1  equivalent  of  oxygen  =    8 

hence  the  chemical  equivalent  of  deutoxide  of  nitrogen  =  22, 
which  was  to  be  proved. 

D  tut  oxide   of  Nitrogen. 

Chemical  composition,  —  1  Equivalent  of  Nitrogen  =  14 
2  Equivalents  of  Oxygen,  (each  being  8)  =  16 


Chemical  equivalent  of  Deutoxide  of  Nitrogen  =30. 

§  49.  The  deutoxide  nf  nitrogen,  like  the  protoxide  of 
the  same  gas  is  not  to  be  found  in  nature.  It  is  a  product 
of  art,  and  may  be  obtained  by  the  action  of  nitric  acid 
(aqua-fortis)  on  some  oxidable  metal,  commonly  copper  or 
quicksilver  (the  latter  is  to  be  preferred).  The  metal 
ought  to  be  put  into  a  retort,  and  the  acid  poured  upon  it, 
when  an  effervescence  will  take  place,  and  the  gas  which 
is  given  off  may  be  collected  through  the  pneumatic  tub. 
To  understand  this  process  it  is  necessary  to  state  that 
nitric  acid  is  :i  combination  of  nitrogen  with  a  greater 
quantity  of  oxygen  than  is  contained  in  the  deutoxide, 
and  that  by  pouring  it  upon  copper  or  mercury,  for  which 


96  NITROGEN. 

oxygen  has  a  strong  affinity,  part  of  its  oxygen  combines 
with  the  metal,  leaving  just  enough  with  the  nitrogen  to 
form  the  deutoxide. 

§50.  Properties  of  Deutoxide  of  nitrogen.  We  have 
already  stated  at  the  head  of  this  article  that  the  deutox- 
ide of  nitrogen  is  a  combination  of  nitrogen  with  a  fur- 
ther portion  of  oxygen.  This  compound  is  a  colorless 
gas,  whose  smell  and  taste  are  not  known,  because  as  soon 
as  it  conies  in  contact  with  the  atmosphere  it  combines 
with  a  fresh  portion  of  oxygen,  and  becomes  converted  in- 
to vapors  of  nitrous  acid.  Jt  is  wholly  irrespirable,  perma- 
nently elastic,  sparingly  soluble  in  water,  arid  does  not,  in 
its  pure  state,  act  upon  vegetable  colors.  It  is  not  inflam- 
mable, and  a  burning  body  immersed  in  it,  is  instantly  ex- 
tinguished ;  but  pieces  of  charcoal  or  phosphorus  intro- 
duced in  a  state  of  vivid  inflammation  burn  in  it  with  great 
splendor,  by  virtue  of  the  oxygen  which  it  contains. 
With  hydrogen  it  may  be  mixed  in  any  proportion  without 
exploding,  but  when  burnt  with  it  in  atmospheric  air,  it 
changes  the  yellow  flame  of  the  hydrogen  into  green. 

When  deutoxide  or  nitric  oxide  is  mixed  with  oxygen 
deep  red  fumes  are  generated,  which,  when  the  experiment 
is  made  over  the  pneumatic  tub,  are  speedily  absorbed 
by  the  water,  so  that  if  the  gases  are  entirely  pure,  and 
mixed  in  the  proper  proportion,  they  will  wholly  disappear. 
If  instead  of  pure  oxygen  common  atmospheric  air  be 
employed,  the  effect  will  be  apparently  the  same;  the 
nitric  oxide  will  combine  with  the  oxygen  of  the  air,  and 
be  absorbed  by  the  water  over  which  the  mixture  is  made, 
the  diminution  in  the  volume  of  the  gases  being  proportion- 
ate to  the  quantity  of  oxygen  contained  in  the  jar. 

Upon  this  property  of  the  deutoxide  of  nitrogen,  to  combine 
with  the  oxygen  in  atmospheric  air,  and  in  this  state  to  be 
absorbed  by*  water,  is  founded  Gay  Lussac's  Eudiometer,  de- 
scribed on  fig.  XCVII,  page  92.  To  a  measured  quantity  of 
atmospheric  air  in  the  tube  (see  that  figure)  is  added  a  suffi- 
cient quantity  of  deutoxide  of  nitrogen  to  combine  with  all 
the  oxygen  contained  in  the  air.  The  tube  is  then  screwed  to 
the  glass  jar,  filled  with  water,  and  the  apparatus  inverted  to 
allow  the  gas  to  ascend  in  the  liquid,  and  to  be  absorbed  by  it. 
When  the  apparatus  is  afterwards  placed  in  its  proper  posi- 


NITROGEN.  97 

tion,  the  diminution  of  oxygen  will  be  perceived  by  the  rise  of 
the  water  and  its  higher  stand  in  the  gradated  tube. 

§  51.  Deutoxide  of  nitrogen  may  be  decomposed  by 
suffering  it  to  stand  over  iron-filings.  A  portion  of  its  oxy- 
gen will  combine  with  the  filings,  and  the  gas  will  by  this 
means  be  converted  into  a  protoxide  (see  §  47).  Its 
composition  (at  the  head  of  this  article)  has  been  inferred 
from  the  fact  that  burning  charcoal  absorbs  exactly  one 
half  of  its  volume,  leaving  the  other  half  pure  nitrogen.  It 
must  therefore  consist  of  equal  volumes  of  nitrogen  and 
oxygen  ;  or,  which  is  the  same,  of 
1  equivalent  or  proportion  by  weight  of  nitrogen  =  14 
and  of  2  equivalents  of  oxygen  (each  being  8)  =  16 

whence  Equiv.  of  Deutoxide  of  Nitrogen  =  30. 

Hyponitrous  Acid. 

Chemical  composition  :       1  equiv.  of  Nitrogen  =14 
3    do.  Oxygen  =  28 


Chemical  equivalent  of  Hyponitrous  acid  =42. 

§  52.  Hyponitrous  acid  is  a  conjectural  or  hypothet- 
ical substance,  which  it  is  supposed  is  formed  from  a  com- 
bination of  the  deutoxide  of  nitrogen,  with  a  further  por- 
tion of  oxygen.  It  is  said  to  be  produced  when  4  volumes 
of  that  gas  are  mixed  with  one  volume  of  oxygen,  making 
the  experiment  over  mercury,  on  top  of  which  a  few  drops 
of  a  solution  of  potash  must  float.  The  deutoxide  of  nitro- 
gen is  then  supposed  to  combine  with  the  oxygen  to  an  acid, 
which  immediately  unites  with  the  potash,  but  which  after- 
wards cannot  be  separated  from  it  without  decomposition. 

Some  chemists*  pretend  that  at  the  common  tempera- 
ture of  the  atmosphere  it  appears  as  an  orange  colored 
vapor,  which  is  exceedingly  injurious  to  the  lungs. 


*  Prof.  Schubert,  of  Berlin,  and  Gmehlea,  in  Heidelberg. 

9 


98  NITROGEN. 

Nitrous  Acid. 

Chemical  composition  :     1  equivalent  of  Nitrogen  =  14 
4  equivalents  of  Oxygen  (each  =  8)  =  32 

Chemical  equivalent  of  Nitrous  acid  =  46 

§  53.  This  gas  may  be  produced  like  the  hyponitrous 
acid,  by  adding  oxygen  to  the  deutoxide  of  nitrogen.  For 
this  purpose  conduct  two  measures  of  the  deutoxide  and 
one  measure  of  oxygen  into  a  glass  retort  fitted  with  a 
stop-cock,  and  from  which  the  atmospheric  air  has  pre- 
viously been  extracted,  either  by  an  air-pump  or  an  ex- 
hausting syringe.  (The  experiment  cannot  be  made  over 
water  or  mercury ;  because  these  liquids  have  too  great 
an  affinity  for  the  compound,  which  would  thus  be  genera- 
ted). The  two  measures  of  the  deutoxide  and  one  measure 
of  the  oxygen  will  be  condensed  into  half  their  volume, 
and  form  a  deep  orange  colored  gas,  which  is  the  nitrous 
acid. 

§  54.  The  combinations  of  nitrogen  and  oxygen 
afford  striking  instances  of  the  direct  proportions  in 
which  gases  combine  with  each  other  by  volumes.  We 
have  seen  that  the  protoxide  of  nitrogen  was  composed 
of  2  volumes  of  nitrogen  with  1  volume  of  oxygen  ;  the 
deutoxide  of  nitrogen  of  2  volumes  of  nitrogen  with  2 
volumes  of  oxygen  ;  and  the  hyponitrous  acid,  being  form- 
ed by  adding  1  volume  of  oxygen  to  the  deutoxide,  is 
equivalent  to  2  volumes  of  nitrogen  with  3  volumes  of  ox- 
ygen ;  finally  the  nitrous  acid  which  is  formed  by  adding 
2  volumes  of  oxygen  to  2  volumes  of  the  deutoxide  is  ev- 
idently equal  to  2  volumes  of  nitrogen  with  4  of  oxygen  ; 
or,  which  is  the  same,  to  1  volume  of  nitrogen  with  2  vol- 
umes of  oxygen. 

This  verifies  what  we  have  stated  in  §  26,  page  76, 
in  reference  to  the  combination  of  the  gases,  which  is 
always  in  the  proportion  of  whole  numbers  by  volume, 
and  in  no  intermediate  ratio,  affording  a  striking  illustra- 
tion of  the  harmony  and  simplicity  of  the  laws  of  nature. 

§  55.  Properties  of  Nitrous  acid.  It  is,  as  we  have 
said,  a  deep  orange-colored  gas,  which  is  capable,  by  vir- 


NITROGEN.  99 

tue  of  its  oxygen,  to  support  the  process  of  combustion, 
and  is  readily  dissolved  by  water,  which  acquires  by  it 
first  a  green,  then  a  blue,  and  finally  a  yellow  tint.  The 
solution  tastes  sour,  reddens  litmus-paper,  and  stains  an- 
imal substances  yellow.  No  great  application  has  been 
made  of  this  acid  in  the  arts. 

Nitric   A  cid. 

Chemical  composition :       I  equivalent  of  Nitrogen  =  14 
5  equivalents  of  Oxygen  (each  8)  =40 

Chemical  equivalent  of  nitric  acid  =  54. 

§  50.  Nitric  acid  (aqua-fortis)  is  found  (in  an  engaged 
state)  combined  with  a  number  of  mineral  and  vegetable 
bases  (Intr.  page  38).  It  is  easily  obtained  by  art,  when 
deutoxide  of  nitrogen  is  passed  very  slowly  into  pure  oxy- 
gen gas,  standing  over  water.  By  this  operation  4  vol- 
umes of  the  deutoxide  combine  with  3  volumes  of  oxygen  ; 
consequently,  as  the  deutoxide  itself  consists  of  1  vol- 
ume of  nitrogen  and  2  of  oxygen,  nitric  acid  will  by  the 
addition  of  3  volumes  of  oxygen,  be  composed  of  1  volume 
of  nitrogen  and  5  of  oxygen  ;  or  by  weight,  of  1  equivalent 
of  nitrogen  and  5  of  oxygen,  as  stated  at  the  head  of  this 
article.  Nitric  acid  may  also  be  procured  from  a  mixture 
of  nitrogen  and  oxygen  placed  over  water  by  passing 
through  it  a  number  of  electric  sparks,  (see  the  appara- 
tus, fig.  LXXXVII,page  74). 

In  a  similar  manner  is  nitric  acid  formed  in  the  atmosphere 
during  a  thunder  storm  ;  indices  of  it  having  been  discovered 
in  rain-water  collected  immediately  after  a  storm. 

§  57.  Nitric  acid  formed  by  art  in  either  manner  we 
have  just  described ,  is  absorbed  by  the  water  over  wh  ich  it  is 
made,  by  which  means  it  is  reduced  to  the  liquid  state ;  and 
so  great  is  the  affinity  of  this  acid  for  water,  that  it  is  doubt- 
ful whether  it  can  ever  be  exhibited  in  an  insolated  state. 

§  58.  Liquid  nitric  odd  is  an  important  article  of 
commerce,  large  quantities  of  it  being  used  in  the  arts. 
For  this  particular  purpose  nitric  acid  is  frequently  distilled 
with  concentrated  sulphuric  acid,  by  which  means  a  most 


100  NITROGEN. 

powerful  acid  is  obtained,  containing  only  little  more  than 
twentyfive  per  cent  of  water  ;  this  being  the  smallest  quan- 
tity of  water  with  which  it  is  known  to  exist.  The  liquid 
acid  is  called  Hydro-nitric  acid,  from  a  Greek  word, 
signifying  water.  But  when  this  acid  combines  again 
with  those  substances  called  bases,  then  the  water  is  given 
off,  and  is  then  said  to  be  in  an  an-hydrous  state. 

§  59.  Properties  of  Nitric  Acid.  Nitric  acid,  or 
aqua-fortis  is  a  highly  corrosive  fluid,  which  oxidates  most 
metals,  and,  with  the  exception  of  tin  and  antimony,  dis- 
solves them  at  a  gentle  heat.  Its  specific  gravity,  when 
most  concentrated,  is  1.5,  that  is,  it  is  about  half  as  heavy 
again  as  water.  It  acts  as  a  powerful  caustic  on  the  skin, 
and  destroys  instantaneously  all  organized  matter.  It  is 
decomposed  by  all  substances  which  have  a  great  affinity 
for  oxygen.  When  heated,  or  brought  in  contact  with  hy- 
drogen, it  detonates  with  great  violence  ;  but  the  experi- 
ment is  somewhat  dangerous.  When  poured  upon  warm 
powdered  charcoal  a  combustion  takes  place,  at  which  the 
deutoxide  of  nitrogen  is  given  off  in  copious  fumes.  Spir- 
it of  turpentine  may  likewise  be  inflamed  by  it,  which 
may  be  shown  by  the  following  pleasing 

EXPERIMENT.  —  Place  some  spirit  of  turpentine,  or  any 

other  essential  oil,  in  a 

Fig.  XCIX.  warm   saucer,  and   pour 

suddenly  some  nitric  acid 
upon  it.  The  carbon 
and  hydrogen  of  which 
turpentine,  and  in  gene- 
al  all  these  oils  are  prin- 
cipally composed,  will 
unite  to  combustion  with 
the  oxygen  of  the  nitric 
acid  ;  and  so  rapid  is  the  inflammation  that  it  is  necessary  to  pour 
the  nitric  acid  from  a  vessel  attached  to  a  long  stick,  in  order 
to  avoid  the  danger  to  which  the  eyes  of  the  experimenter 
would  inevitably  be  exposed  if  standing  too  near. 

§  60.  Application  of  Nitric  acid  to  the  arts.  Nitric 
acid  is  one  of  the  most  powerful  means  of  attaining  the 
various  ends  proposed  in  chemical  investigations,  or  in  the 


NITROGEN.  101 

arts.  Its  great  application  is  founded  partly  upon  its  capa- 
city in  union  with  water  to  dissolve  most  solid  substances 
and  partly  upon  the  small  cohesive  attraction  between 
its  particles,  in  consequence  of  which  it  is  easily  decom- 
posed and  yields  its  oxygen  to  other  substances  with 
which  it  is  brought  in  contact.  To  the  gold  and  silver- 
smith it  is  a  means  of  separating  one  metal  from  an- 
other. The  dyer  and  cotton  printer  use  it  in  the  prepa- 
ration of  various  metallic  salts,  for  the  purpose  of  produc- 
ing different  shades  of  colors.  The  artificer  in  bronze 
employs  its  solving  power  to  cleanse  the  products  of  his 
art  from  various  oxides  and  other  impurities  ;  the  engraver 
uses  it  in  the  process  of  etching ;  the  turner  finds  it  useful 
in  dying  ivory  and  wood  :  and  so  might  we  continue  to 
transcribe  a  long  catalogue  of  the  useful  applications 
which  are  made  of  this  acid  in  the  arts,  were  it  not  incon- 
sistent with  the  limits  proposed  in  this  treatise. 

Combination  of  Nitrogen  with  Hydrogen  — Ammonia. 

Chemical  composition:     1  equivalent  of  Nitrogen  =  14 
3  equivalents  of  hydrogen  (each  being  1)  =    3 


Consequently,  Equivalent  of  Ammonia  =  17. 

§  61.  Ammonia,  the  compound  of  nitrogen  with  hy- 
drogen, is  noffound  in  nature  in  its  free  state  ;  but  occurs 
combined  with  acids  from  the  mineral  and  vegetable 
kingdoms.  It  is  best  obtained  from  a  mixture  of  equal 
volumes  of  powdered  sal-ammoniac  and  quicklime,  gently 
heated  in  a  retort.  The  gas  will  be  given  off  in  great 
quantities,  but  must  be  collected  over  quicksilver,  water 
absorbing  it  too  fast.  When  the  experiment  is  made  over 
water,  which  takes  up  more  than  500  times  its  own  bulk,  an 
aqueous  solution  of  ammoniais  formed,  which  is  an  article  of 
great  use,  and  possesses  all  the  essential  qualities  of  the  gas. 

This  solution  of  ammonia  has  received  the  several  appella- 
tions of  spirits  of  sal-ammoniac,  spirits  of  hartshorn,  or  liquid 
ammonia,  and  is  extensively  employed  by  druggists.  The 
salt  contained -in  smelling  bottles  is  a  carbonate  of  ammonia 
which  will  be  described  in  the  4th  Chapter. 

9* 


102  NITROGEN. 

§  62.  Properties  of  Ammonia.  Ammonia  is  a  color- 
less gas  of  an  extremely  pungent  smell,  and  a  sharp,  burn- 
ing taste.  It  changes  blue  vegetable  colors  into  green, 
and  yellow  into  brown,  and  is  very  much  lighter  than  at- 
mospheric air,  100  cubic  inches  of  it  weighing  only  18 
grains.  It  is  totally  irrespirable,  and  when  accidentally 
taken  into  the  lungs  causes  cramp  and  suffocation.  An 
animal  plunged  into  it  immediately  dies.  Neither  is  it  fit 
to  support  the  process  of  combustion  ;  nor  is  it  itself  com- 
bustible in  atmospheric  air,  but  in  pure  oxygen  it  burns 
with  a  yellow  flame.  It  loses  its  elasticity  and  becomes 
liquid  at  a  pressure  equal  to  195  perpendicular  inches  of 
quicksilver,  or  by  a  temperature  of  40  degrees  below 
zero  of  Fahrenheit's  thermometer. 

From  the  manner  in  which  we  have  just  stated  that  ammo- 
nia affects  vegetable  colors,  and  from  the  remarkable  property 
which  it  possesses  to  combine  with  the  acids  to  salts,  it  is  evi- 
dent that  ammonia  belongs  to  that  class  of  bodies  which  are 
called  bases  (see  Intr,  page  38).  It  is  therefore  called  the 
volatile  alkali,  to  designate  its  basic  nature,  and  at  the  same 
time  to  distinguish  it  from  the  vegetable  and  mineral  alkalis, 
which  are  likewise  capable  of  neutralizing  the  acids  and  form 
salts  with  them.  (See  Chapter  VI.) 

§  63.  When  ammonia  is  passed  through  narrow  red- 
hot  tubes,  especially  if  some  iron  wire  be  coiled  up  in 
them,  it  is  again  decomposed  into  its  elements,  nitrogen 
and  hydrogen  ;  yielding  by  volume,  three  times  as  much 
hydrogen  gas  as  nitrogen,  which  proves  the  correctness  of 
its  chemical  composition  as  before  stated.  It  is  also  de- 
composed by  a  series  of  electric  sparks,  and  when  mixed 
with  oxygen  may  be  ignited  like  a  mixture  of  oxygen  and 
hydrogen. 

Recapitulation  of  the  most  important  binary  combinations 
of  Nitrogen. 

Protoxide  of  nitrogen. 
\Deutoxide  of  nitrogen. 


.Nitric 
Hydrogen  to  Ammonia. 


CHLORINE.  103 


D.     Chlorine. 

Chemical  Equivalent  =  36. 

§  64.  This  is  the  fourth  and  last  of  the  gaseous  ele- 
ments which,  although  not  found  in  its  simple  state  in  na- 
ture, is  easily  procured  in  the  manner  we  are  about  to  de- 
scribe. It  is  found  combined  with  most  of  the  metals,  or 
united  with  hydrogen.  By  art  it  may  either  be  produced 
by  the  action  of  muriatic  acid  upon  a  substance  called 
black  oxide  of  manganese;  or  it  may  also  be  obtained  in  a 
cheaper  way,  by  adding  3  parts  of  finely  powdered  sea- 
salt  to  one  part  of  the  same  oxide,  and  pouring  upon  them 
in  a  retort  two  parts  of  diluted  sulphuric  acid.  By  the 
application  of  a  gentle  heat,  chlorine  will  be  given  off  in 
great  quantities,  which  may  be  collected  by  the  pneumatic 
tub,  employing  hot  water  or  quicksilver  for  this  purpose  ; 
because  cold  water  absorbs  the  gas  too  rapidly.  The  gas 
obtained  in  this  manner  may  be  preserved  in  glass-bottles 
with  greased  stoppers,  taking  great  care  to  expel  all  water 
from  them. 

§  65.  Properties  of  Chlorine.  Chlorine  is  a  gas  of  a 
yellowish  green  color  (whence  its  name,  from  a  Greek 
word  signifying  green),  which  has  an  astringent  (not  acid) 
taste,  and  a  disagreeable)  suffocating  smell.  When  inhal- 
ed it  is  exceedingly  injurious  to  the  lungs,  and  may  pro- 
duce instant  death.  An  animal  confined  in  it  is  almost 
instantaneously  killed.  It  is  not  inflammable,  but  it  is 
capable  of  supporting  the  combustion  of  some  substances, 
such  as  phosphorus,  arsenic,  bismuth,  antimony,  &c. 
Mixed  with  vapors  of  water  it  becomes  liquid,  but  concen- 
trates again  into  a  yellow  solid  substance  when  surrounded 
by  snow  or  ice.  Its  specific  gravity  is  2.5,  that  of  atmos- 
pheric air  being  1  ;  it  is  consequently  two  and  a  half 
times  as  heavy  as  atmospheric  air  ;  100  cubic  inches 
weighing  76£  grains,  while  the  same  quantity  of  air  weighs 
only  30^  grains.  Combined  with  lime  it  forms  chloride 
of  lime,  a  substance  also  known  by  the  name  of  bleaching 
powder,  on  account  of  its  possessing  the  remarkable  prop- 
erty of  destroying  all  animal  and  vegetable  colors.  Of 


104  CHLORINE. 

this    substance    we    shall    speak    more    fully    in  the   4th 
chapter,  in  treating  of  the  salts. 

Chlorine  being  specifically  heavier  than  atmospheric  air,  is 
one  of  those  gases  which  may  be  transferred  from  one  vessel  to 
another  without  the  assistance  of  the  pneumatic  tub.     Indeed, 
P.      p  suppose  we  had  been  preparing 

chlorine  in  the  retort  A.  It 
would  only  be  necessary  to  in- 
troduce a  pipe  through  the  cork 
of  this  retort  to  conduct  the  gas 
into  an  open  vessel,  into  which 
it  would  descend  in  consequence 
of  its  specific  gravity.  But  chlo- 
rine collected  in  this  manner 
combines  always  with  a  portion 
of  vapor  of  water  contained  in 
the  atmospheric  air  ;  it  is  there- 
fore better  to  collect  it  over  hot  water  or  quicksilver. 

The  property  of  chlorine  to  support  the  combustion  or  to 
ignite  some,  of  the  metals,  may  be  illustrated  by  the  following 
pleasing 

EXPERIMENT.  —  Fill  a  long  bottle  or  tube  with  chlorine,  and 
cover  its  mouth  by  a  plate  of  glass.  Provide  some  powdered 
antimony,  which,  upon  sliding  off  the  cover,  pour  into  the  glass. 
The  metal  will  ignite  before  it  reaches  the  bottom,  and  affords 
a  beautiful  shower  of  white  flames.  Tin,  copper,  zinc,  arse- 
nic, or  even  gold  introduced  in  a  state  of  minute  division,  af- 
ford the  same  experiment. 

Combinations  of  Chlorine  ivith  Oxygen. 

<§,  66.  Chlorine  combines  with  oxygen  in  four  different 
proportions,  forming  with  it  two  oxides  and  two  acids, 
viz  :  Protoxide  of  Chlorine,  Peroxide  of  Chlorine,  Chlo- 
ric acid,  and  Perchloric  acid.  Neither  of  these  com- 
pounds has  ever  been  found  in  nature,  nor  has  any  appli- 
cation been  made  of  them  in  the  arts. 

Protoxide  of  Chlorine 

is  composed  of  1  equivalent  of  Chlorine  =  36 
1          do.  Oxygen  =    8 

Consequently,  chemical  equiv.  of  Prot.  of  Chlorine  =  44. 
It  is  a  deeper  colored  gas  than  chlorine  ;    its  smell  is 


CHLORINE.  105 

somewhat  like  burnt  sugar.  It  is  obtained  from  heated 
chlorine  of  potash  mixed  with  very  dilute  muriatic  acid, 
and  consists,  by  volume,  of  2  volumes  of  chlorine  with  1 
volume  of  oxygen. 

Peroxide  of  Chlorine 

consists  of  1  equivalent  of  chlorine  =  36 
and  of  4  equivalents  of  oxygen  (each  =  8)  =  32 

Chemical  equivalent  of  Peroxide  of  Chlorine  =  68. 

Properties.  It  is  of  a  yellow  color,  smells  like  chlorine, 
has  a  very  disagreeable  astringent  taste,  and  is  speedily 
absorbed  by  water.  It  is  obtained  by  the  action  of  sul- 
phuric acid  on  chlorate  of  potash,  and  is  composed,  by 
volume,  of  2  volumes  of  chlorine  with  4  volumes  of  oxygen. 

Chloric  acid 

is  composed  of  1  equivalent  of  chlorine  =  36 
5  equivalents  of  oxygen  (each  =  8)  =  40 

Chemical  equivalent  of  Chloric  acid  =76. 

Properties.  It  is  colorless,  always  mixed  with  a  small 
portion  of  water,  consequently  liquid,  has  an  astringent 
taste,  and  reddens  blue  vegetable  colors.  It  is  obtained 
from  the  decomposition  of  a  salt  called  Chloride  of  Baryta 
by  means  of  diluted  sulphuric  acid,  and  consists  of  two 
volumes  of  chlorine  with  5  volumes  of  oxygen. 

Per-chloric  Acid 

consists  probably  of  1  equivalent  of  chlorine  =    36 
8  equivalents  of  oxygen  (each  =8)  =    64 


Chemical  equivalent  of  Per-chloric  acid  =  100. 

It  is  the  fourth  and  last  of  the  combinatians  of  chlorine 
with  oxygen,  and  its  chemical  composition  is  not  precisely 
known.  It  is  colorless,  inodorous,  and  has  a  pure  sour 
taste.  It  consists  of  2  volumes  of  chlorine  with  v8  volumes 
of  oxygen. 

REMARK. — There   exists  a  difference  in  the   opinions   of 


106  CHLORINE. 

distinguished  chemists  with  regard  to  the  composition  of  the 
two  compounds,  peroxide  of  chlorine  and  per-chloric  acid.  We 
have  stated  that  the  peroxide  consists  of  two  volumes  of  chlo- 
rine and  four  volumes  of  oxygen.  This  however  is  doubted, 
and  the  composition  of  this  compound  stated  by  some  chemists 
as  two  volumes  of  chlorine  and  three  volumes  of  oxygen.  If 
this  be  true,  its  composition  is 

1  equivalent  of  chlorine  =  36 
3        do.         of  oxygen  =  24 

.     Chemical  equivalent  of  peroxide  of  chlorine  =60. 

and  not  68  as  before  stated. 

Again,  we  have  stated  the  chemical  equivalent  of  per- 
chloric acid  to  be  100.  This  substance  however,  is  by  some 
chemists  believed  to  be  compounded  of 

1  equivalent  of  chlorine  =  36 
7  equivalents  of  oxygen  =  56 

consequently,  chemical  equivalent  of  per-chloric  acid  =92. 
Compare  this  with  the  remark  on  page  15. 

Combinations    of    Chlorine   with    Hydrogen  —  Muriatic 
Acid. 

Chemical  composition  :     I  equivalent  of  chlorine  =  36 
1          do       of  hydrogen  =    I 

Consequently,  Chemical  equiv.  of  muriatic  acid  =  37. 

§  67.  Chlorine  and  hydrogen  combine  together  to 
muriatic  acid.  This  compound  is  found  in  nature  in  form 
of  vapors,  or  also  in  a  liquid  state,  particularly  in  the 
neighborhood  of  volcanos,  as  for  instance  in  the  vicinity 
of  Rio  Vinagre,  in  South  America.  But  it  may  also  be 
obtained  by  the  mysterious  influence  of  solar  light.  A 
mixture  of  hydrogen  and  oxygen,  well  secluded  from  the 
light,  will  remain  unchanged  for  any  length  of  time.  But 
if  the  mixture  is  made  of  equal  volumes,  of  these  gases  and 
exposed  to  the  light  of  day  (in  the  shade),  they  gradually 
combine  without  change  of  volume  to  a  powerful  acid,  in 
which  the  peculiar  smell  and  odor  of  chlorine  will  no 
longer  be  perceptible.  If  the  mixture  be  directly  exposed 
to  the  light  of  the  sun,  then  the  combination  takes  place 
suddenly  and  is  attended  by  an  explosion.  (The  mixture 
may  also  be  exploded  by  an  electric  spark  or  the  flame  of 


CHLORINE.  107 

a  candle).  Muriatic  acid  gas  may  also  be  procured  in  a 
much  cheaper  way  by  the  action  of  strong  sulphuric  acid 
on  sea-salt.  The  gas  obtained  in  either  way  must  be 
collected  over  mercury,  (by  the  pneumatic  tub  filled  with 
mercury  instead  of  water)  its  affinity  for  water  being  so 
great  that  an  unstopped  vessel  filled  with  it  and  placed  un- 
der water,  will  in  a  few  moments  be  entirely  filled  with 
the  liquid,  the  gas  being  wholly  absorbed. 

§  68.  Properties  of  Muriatic  Acid.  It  is  a  colorless 
gas,  of  a  very  pungent  smell  and  strong  acid  taste.  It 
turns  blue  vegetable  colors  into  red,  and  in  contact  with 
the  atmosphere  forms  dense  white  clouds,  (in  consequence 
of  its  combining  with  the  steam  or  vapor  contained  in  at- 
mospheric air).  By  a  pressure  of  about  1120  perpendicu- 
lar inches  of  quicksilver  (equal  to  about  40  times  trie 
pressure  of  our  atmosphere)  it  becomes  liquid,  but  it  is 
neither  combustible  nor  respirable,  nor  is  it  capable  of 
supporting  the  process  of  combustion.  In  contact  with 
the  oxides  it  loses  its  hydrogen,  which  combines  with  the 
oxygen  of  the  oxide  to  water,  setting  the  chlorine  free. 
This  explains  the  process  by  which  chlorine  is  obtained 
from  the  operation  of  muriatic  acid  on  black  oxide  of  man- 
ganese. (See  §  64,  page  103). 

§  69  When  muriatic  gas  is  conducted  into  water,  it 
is  rapidly  absorbed  by  this  liquid,  by  which  means  liquid 
muriatic  acid  is  obtained  ;  a  substance  similar  in  prop- 
erties to  the  muriatic  acid  gas,  and  of  great  usefulness  and 
application  in  chemistry  and  the  arts.  For  this  purpose 
Woulf's  apparatus  is  generally  employed.  It  consists  of 

Fig.  CI. 


B 


108  CHLORINE. 

a  number  of  glass  bottles  shaped  as  in  figure  CI.     The 
bottles   A  and   B,  of  which  there    may    be    any  number 
we  please,  are  each  provided  with  three  necks,  and   con- 
tain a  quantity  of  water,  which  is  to  be  impregnated  with 
the  gas.     When  liquid  muriatic  acid,  or  as  it  is  sometimes 
called,  hydro-muriatic  acid,  is  to  be  formed,  common  salt 
is  put  into  the  retort  R,  and  a  small  quantity  of  dilute 
sulphuric  acid  poured  upon  it.     When  a  gentle  heat  is 
applied  to  the  retort  muriatic  acid  gas  is  given  off,  which 
passes  into  the  globe  G,  destined  to  condense  such  por- 
tions of  vapor   as   would   render  the   gas  impure.     From 
the  globe   the  gas  passes  through  the  bent  tube  P,  into 
the  first  bottle  A.      The   water   in  this  bottle   will   ab- 
sorb a  portion  of  the  gas,  and  the  remainder  will  pass 
through  the  tube  Q,  into  the  next  bottle,  and  so  on.     The 
bent  tubes  P,  Q,,  &c,  (see  the  figure),  are  a  little  above 
the  surface  of  the  preceding  bottle,  and  dip  below  the  sur- 
face of  the  liquid  in  the  other,  in  order  to  allow  the  gas  to 
escape  from  one  bottle,  and  to  impregnate  the  water  in  the 
other.     The  process  must  be  carried  on  until  the  water 
in  all  the  bottles  is  completely  saturated.    (See  Intr.  page 
8).     To  promote  the   absorption  of  the   gas,  the  bottles 
may  be  placed  in  ice.     The  last  bottle  must   be  provided 
with  an  open  tube  to  allow  the  escape  of  atmospheric  air, 
or  such  other  gas  as  the  water  will  not  absorb.     The  per- 
pendicular tubes   a,  b,  are  safety  tubes,  to  admit  atmos- 
pheric air  into  each  bottle  when  the  gas  ceases  to  come 
over  from  the  retort ;  for  in  this  case  a  vacuum  would  be 
created  in  the  globe  G,  (from  which  the  gas  is  absorbed  by 
the  water  in  the  first  bottle),  into  which  the  pressure  of 
atmospheric  air,  acting  through  the  open  tube  S,  would 
force  the  saturated  liquid,  which  would  then  be  rendered 
impure,  by  mixing  with  the  impurities  and  vapors  deposit- 
ed in  G.  The  liquid  muriatic  acid  thus  obtained,  possesses 
all  the  essential  qualities  of  the  gas. 

When  prepared  on   a  large  scale  vessels   of  iron    are 

usually  employed  instead  of  glass.     This  is  probably  the 

reason  why  the  liquid  muriatic  acid  of  commerce  contains 

usually  a  little  iron,  which  gives  it  a  faint  yellow  tint. 

The  applications  of  muriatic  acid  are  almost  as  numer- 


CHLORINE.  109 

ous  as  those  of  nitric  acid.  It  is  used  in  the  art  of  bleach- 
ing, and  is  able  to  dissolve  most  solid  substances,  particu- 
larly metals.  It  operates  very  powerfully  on  metallic  ox- 
ides and  forms  with  some  of  them  (such  as  oxides  of  lead 
or  silver)  insoluble  compounds.  Mixed  with  nitric  acid  it 
forms  the  well  known  aqua  regia*  the  only  liquid  which 
dissolves  gold,  and  is  on  that  account  useful  to  the  gold- 
smith. Combined  with  oxide  of  tin.  it  is  used  in  the 
processes  of  dying  and  calico-printing.  It  is  also  employ- 
ed in  the  extraction  of  animal  gluten  from  the  bones,  for 
various  medicinal  purposes. 

Combination    of    Chlorine  ivith  Nitrogen.  —  Chloride  of 
Nitrogen. 

Chemical  composition  :     4  equivalents  Chlorine 

(each  36)=  144 
1  equivalent    Nitrogen  =    14 

Chemical  equivalent  of  Chloride  of  Nitrogen  =  J5S. 

§  70.  This  compound  of  chlorine  was  discovered  by 
Dulong,  a  celebrated  French  chemist.  Chlorine  and  ni- 
trogen have  but  a  feeble  affinity  for  each  other  ;  but  when 
chlorine  is  passed  through  a  solution  of  nitrate  of  ammo- 
nia at  a  temperature  of  about  90  degrees  Fahrenheit,  then 
the  chlorine  is  rapidly  absorbed,  and  an  oily  film  first  ap- 
pears on  the  surface  of  the  solution,  and  finally  sinks  to 
the  bottom  of  the  vessel.  This  oily  liquid  is  chloride  of 
nitrogen. 

To  understand  what  we  have  just  said,  it  is  necessary  to 
state  that  nitrate  of  ammonia  is  a  compound  of  nitric  acid  and 
ammonia,  nitric  acid  being  composed  of  nitrogen  and  oxygen. 
The  oily  globulge  which  sink  to  the  bottom  are  formed  by  the 
decomposition  of  the  nitrate  of  ammonia,  the  nitrogen  combin- 
ing with  the  chlorine.  If  a  flat  vessel  be  placed  at  the  bottom 
of  the  solution,  the  compound  may  be  collected  in  it, 

§71.     Properties  of  Chloride  of  Nitrogen.     Chloride 

of  nitrogen  in  a  yellowish  oily  liquid,  which  does  not  be- 



*  Signifying  king's  water,  because  it  dissolves  gold,  which  by  the 
alchemist  was  called  the  king  of  metals. 

10 


110  RECAPITULATION 

come  solid  by  great  degrees  of  artificial  cold.  Tts  specific 
gravity  is  1.653  that  of  water  being  I  ;  and  it  is  the  most 
powerfully  explosive  substance  known.  It  should  there- 
fore be  handled  with  great  caution,  and  not  be  experiment- 
ed upon  in  quantities  larger  than  a  grain  of  mustard  seed, 
and  even  then  with  great  caution.*  It  explodes  at  a  tem- 
perature of  about  200  degrees  Fahrenheit,  but  detonates 
in  contact  with  a  combustible  substance  at  the  common 
temperature  of  the  atmosphere.  A  single  drop  of  it 
thrown  into  turpentine  or  olive  oil  causes  so  violent  an  ex- 
plosion as  to  burst  the  phial. 

This  phenomenon  is  explained  by  the  great  volume  of  the 
two  gases,  nitrogen  and  chlorine,  which  are  engaged  in  the 
formation  of  chloride  of  nitrogen,  and  which  become  suddenly 
free  ,and  by  the  expansion  of  their  volume  cause  the  explosion 
when  brought  in  contact  with  a  combustible  substance. 

Recapitulation    of  the  principal  binary  Combinations  of 
Chlorine,  t 

Sr  Protoxide  of  Chlorine. 
„,„„„  .        Peroxide  o    Chlorine. 


Hydrogen  to  Muriatic  Acid. 
Nitrogen  to  Chloride  of  Nitrogen. 


RECAPITULATION. 

Questions  for  reviewing  some  of  the  most  important  Prin- 
ciples contained  in  the  1st  Chapter. 

A.     QUESTIONS  ON  OXYGEN. 

[§  1.]  What  are  the  principal  properties  of  oxygen  1 
Is  the  presence  of  oxygen  absolutely  indispensable  to  an- 
imal life  ? 

*  See  Library  of  Useful  Knowledge. 
\  See  article  Chlorides,  in  Chap.  IV . 


OF     CHAPTER    I.  Ill 

[§  2.]  Describe  some  of  the  ways  in  which  oxygen  is 
obtained. 

[§  3.J  What  is  that  process  called,  by  which  oxygen 
combines  with  other  simple  and  compound  bodies'? 

[§  4.]  How  many  different  names  are  given  to  the  ox- 
ides ?  To  what  substance  is  the  name  of  Protoxide  given  ? 
What  is  a  Deutoxidc  ?  What  a  Peroxide  ?  By  what 
means  do  we  distinguish  between  the  names  of  the  differ- 
ent acids  ?  What  does  the  name  of  the  acid  in  ic  indicate  ? 
What  that,  terminating  in  ous  1  What  does  the  name  of 
hypo  signify  when  put  before  the  name  of  an  acid  ? 

Give  examples. 

[§  5.]  In  what  consists  the  combustion  or  burning  of 
bodies  ?  What  is  every  body  called  which  is  capable  of 
such  a  combination  with  oxygen  ? 

What  was  the  phlogiston  of  the  ancients  ? 

[§  6.]  What  do  most  bodies  require  for  their  combus- 
tion 1  Give  examples. 

Explain  the  process  of  a  burning  lamp  or  candle. 

[§  7.]  Is  the  light  which  is  given  out  during  the  pro- 
cess of  combustion  always  the  same,  or  is  it  subject  to  va- 
riation in  intensity  and  color  ? 

Give  examples. 

[§  8.]     How  do  all  bodies  burn  in  oxygen  ? 

Give  examples.     (Explain  Figs.  LXIV,  LXV,  LXVI.) 

What  do  these  examples  prove  with  regard  to  the  heat  pro- 
duced by  combustions  in  pure  oxygen  ? 

[§  9.]  When  the  whole  product  of  combustion  is 
weighed,  is  it  found  heavier  or  lighter  than  the  substance 
was  before  the  combustion  1  Give  an  example. 

But  why  do  the  ashes  produced  by  burning  wood  or  straw 
weigh  less  than  the  wood  or  straw  before  the  combustion  ? 
When  the  inflammable  gas  which  is  given  off  during  the 
combustion  of  these  substances  is  collected,  and  its  weight 
added  to  that  of  the  ashes,  is  the  sum  of  their  weight 
greater  or  less  than  that  of  the  wood  or  straw  before  the 
combustion  ? 


112  RECAPITULATION 

[§  10.]  Can  any  combustion  take  place  without  the 
presence  of  oxygen  ?  How  long  therefore  can  the  com- 
bustion of  oxygen  only  be  continued  ? 

What  experiment  can  you  describe  to  prove  your  assertion  r 
(Explain  Fig.  LX VII).  What  alteration  will  take  place,  if  in 
your  experiment,  you  employ  atmospheric  air  instead  of  pure 
oxygen?  What  does  the  slower  burning  of  the  candle  in 
common  atmospheric  air  prove  ?  Why  does  the  water  rise 
higher  in  the  receiver  when  pure  oxygen  is  used  ?  Why  does 
the  candle  become  extinguished  when  21  per  cent  of  the 
whole  air  contained  in  the  receiver,  are  consumed?  What  is 
required  for  a  complete  combustion  of  bodies  in  oxygen  or  at- 
mospheric air?  (Explain  Pig.  LXVIII).  What  remarkable 
coincidence  is  there  between  the  processes  of  respiration 
and  combustion  ? 

[§  11.]  By  what  is  the  quantity  of  air  necessary  for 
combustion,  supplied  ?  What  do  you  call  a  draft?  For 
what  purpose  are  fire-places  and  chimneys  built? 

How  are  smoking  fire-places  improved  ?  Why  is  the  flame 
of  an  Argand's  lamp  brighter  than  that  of  a  common  lamp  ? 

[§  12.]  How  is  fire  extinguished  ?  By  what  means  is 
this  effected  ? 

Why  are  small  quantities  of  water  of  little  use  in  the  extin- 
guishing of  conflagrations  ? 

[§  13.]  Is  the  combination  of  oxygen  with  other  sub- 
stances always  accompanied  by  the  phenomenon  of  fire  ? 
In  what  cases  is  it  not  ? 

Give  instances  of  such  combinations. 

[§  14.]  In  what  does  the  process  of  desoxidation 
consist  ?  In  how  many  different  ways  is  it  effected  ?  What 
are  they  ? 

B.     QUESTIONS  ON  HYDROGEN. 

[§  15.]  What  becomes  of  water  when  subjected  to 
the  action  of  galvanic  electricity  ?  Explain  Figs.  LXIX, 
LXX,  and  LXXI.  What  is  most  remarkable  about  this 
decomposition  of  water  ? 


OFCHAPTERI.  113 

[§  16.]  What  are  the  characterizing  properties  of 
hydrogen  ? 

Explain  the  two  experiments  represented  in  Figs.  LXXII, 
and  LXXIII  (page  62).  In  what  manner  can  hydrogen  gas  be 
transferred  from  one  vessel  to  another  ?  Explain  the  experi- 
ment represented  in  Fig.  LXXIV. 

By  what  experiment  can  you  show  the  levity  of  hydrogen 
gas  ?  Explain  Fig.  LXXV.  How  does  the  experiment  you 
have  just  described  enable  us  to  find  the  specific  gravity  of 
hydrogen  ?*  Describe  the  experiment  represented  in  fig. 
LXX  VI,  which  shows  the  levity  and  combustibility  of  hydrogen. 

[§  17.]  Is  galvanic  electricity  the  only  means  of  ob- 
taining hydrogen  gas?  What  other  means  have  we  for 
procuring  this  gas  1  (Explain  Figs.  LXXVII,  and 
LXXVIII.) 

[§  18.]  How  is  the  great  levity  of  hydrogen  gas  taken 
advantage  of?  (Explain  Fig.  LXXIX).  In  what  con- 
sists the  construction  of  balloons  for  ascending  in  the  air  ? 
(Explain  Fig.  LXXX). 

[§  19.]  In  what  proportions  may  oxygen  be  mixed 
with  hydrogen  ?  Is  there  a  strong  affinity  between  the 
substances  ? 

By  what  experiment  can  you  prove  this  ?  Explain  the  ex- 
periment represented  in  Fig.  LXXXt.  In  what  manner  does 
Prof.  Schubert  account  for  the  explosion  accompanying  the 
combustion  of  inflammable  air  ? 

[§  20.]  What  is  formed  when  one  volume  of  hydro- 
gen gas  is  mixed  with  two  volumes  of  atmospheric  air  ? 

Explain  Fig.  LXXXII.  Explain  the  experiment  represented 
in  Fig.  LXXXIII. 

[§  21.]  What  is  the  most  important  application  made 
of  the  properties  of  inflammable  air  to  various  chemical 
purposes  ?  Explain  Fig.  LXXXIV.  What  are  the  effects 
of  Dr  Hare's  compound  blow-pipe  ? 

[§  22.]     What  is   the  construction  of  the    blow-pipe 

*  This  question  need  not  be  put  to  very  young  pupils. 
10* 


114  RECAPITULATION 

with   condensed   oxygen   and   hydrogen  1      Explain    Fig. 
LXXXV.     How  is  the  apparatus  used  ? 

[§  23.]  Describe  the  experiment  (represented  in  Fig. 
LXXXVI)  by  which  water  is  formed  by  the  combustion 
of  hydrogen  ?  What  inference  do  you  draw  from  this 
experiment  with  regard  to  the  nature  of  water  1 

[§  24.]  In  what  proportion  do  hydrogen  and  oxygen 
combine  to  water?  By  what  experiment  can  you  prove 
that  water  consists  of  two  volumes  of  hydrogen  combined 
with  one  volume  of  oxygen  1  Explain  Fig.  LXXXVII. 
What  does  this  experiment  serve  to  establish  1 

[§  25.]  Of  how  many  equivalents  of  hydrogen  and 
oxygen  does  water  consist  ?  What  is  the  equivalent  num- 
ber of  oxygen?  What,  that  of  hydrogen  ?  What,  there- 
fore that  of  water  ? 

[§  26.]  What  remarkable  law  has  been  discovered  in 
reference  to  the  combinations  of  the  gases  ? 

[§  27.]  What  are  the  most  essential  properties  of  wa- 
ter? What  is  the  weight  of  a  cubic  inch  of  distilled  wa- 
ter ?  At  what  degree  of  Fahrenheit's  scale  is  the  greatest 
density  of  water?  What  is  the  condensation  of  oxygen 
and  hydrogen  in  the  act  of  forming  water. 

How  does  the  sudden  diminution  in  the  volume  of  the 
two  gases  account  for  the  heat  given  out  during  the  combus- 
tion of  hydrogen  ? 

What  influence  has  this  peculiarity  of  water  —  te  be  most 
dense  at  40  degrees  Fahrenheit —  have  upon  the  economy  of 
nature  ?  What  would  become  of  the  waters  in  the  northern 
regions,  if  water  did  not  possess  this  property  ? 

[§  28.]  Does  water  in  the  act  of  freezing  or  congeal- 
ing expand  or  contract  in  volume  ?  What  phenomena 
does  this  explain  ?  What  is  the  specific  gravity  of  ice  ? 
What  is  this  the  reason  of  ? 

[§  29.]  Which  of  the  three  kinds  of  water,  rain,  riv- 
er, or  pump  water,  is  the  purest  ?  Why  ?  Which  comes 
next  to  it  ?  What  are  the  first  two  kinds  called  in  oppo- 
sition to  pump  water  ?  What  does  pump  water  always 


OF    CHAPTER    I.  115 

contain?     What  are  the  ingredients  of  mineral  waters'? 
What  are  the  principal  salts  contained  in  sea-water? 

[§  30.]  What  do  all  kinds  of  water  contain  ?  Do 
they  contain  atmospheric  air  as  a  chemical  ingredient,  or 
merely  mechanically  entangled?  By  what  means  may 
water  be  freed  from  it  ? 

[$  31.]  Is  water  a  good  conductor  of  heat?  What 
experiment  convinces  us  that  water  is  a  bad  conductor  of 
heat? 

Describe  the  experiment  represented  in  Fig.  LXXXVIII. 
Explain  the  experiment  repieseuted  in  Fig.  LXXXIX. 

Could  water  be  heated  without  the  mobility  of  its  particles? 
Why  not?  What  then,  is  the  reason  why  burning  ether  on 
the  surface  of  water  does  not  affect  a  small  thermometer  im- 
mersed in  the  water  ? 

[§  32.]  Does  the  pressure  of  the  atmosphere  or  of 
steam  promote  or  hinder  the  boiling  of  water  and  other 
liquids  ?  What  is  this  the  reason  of?  How  can  this  be 
illustrated  ?  (Describe  the  experiment  represented  in  the 
XCth  figure). 

What  does  this  experiment  prove?  What  inference  can 
you  draw  from  the  experiment  just  described,  with  regard  to 
the  boiling  of  water  or  other  liquids  ? 

[§  33.]  What  does  water  constantly  absorb  ?  Into 
what  does  it  thereby  become  converted  ?  Of  what  use  is 
the  absorption  of  heat  or  caloric  by  the  large  waters  on 
the  surface  of  our  globe  ?  What  is  the  continued  forma- 
tion of  vapors  from  the  surface  of  water  called  ?  What  do 
the  vapors  of  water  contained  in  the  atmosphere,  form  ? 
what  becomes  of  these,  when  brought  in  contact  with  cold- 
er strata  of  air  ? 

By  what  experiment  may  the  refrigerating  influence  of 
forming  vapors  of  liquids  be  illustrated  ?  Describe  the  exper- 
iment represented  in  Fig.  XCI. 

What  other  illustration  is  there  of  the  cold  produced  by 
the  rapid  process  of  evaporation  ? 

Describe  Dr  Wallaston's  Cryopborus  or  Frost-bearer,  and 
its  operation.  By  what  other  natural  processes  are  the  effects 
of  evaporation  happily  illustrated  ?  How  does  the  process  of 


116  RECAPITULATION 

evaporation  operate  upon  the  human  body?  Why  is  it  dan- 
gerous to  be  exposed  to  a  current  of  cold  air  when  the  clothes 
have  become  moist  with  perspiration  ? 

[§  34.]  What  is  necessary  to  obtain  water  in  its  pure 
state  ?  By  what  process  may  small  quantities  of  water 
be  distilled?  (Explain  Fig.  XCIII).  What  properties 
does  the  water  thus  obtained  possess  ? 

[§  35.]  What  becomes  of  all  the  heat  or  caloric  that 
is  added  to  boiling  water  ?  What  is  steam  which  is  shut 
up  in  a  vessel  capable  of  exercising  ?  To  how  many 
times  its  volume  may  water  thus  be  expanded  ? 

By  what  experiment  may  the  principal  properties  of  steam 
be  illustrated  ?  Describe  the  experiment  represented  in  fig. 
XCIV.  Why  is  the  piston  in  your  experiment  driven  down 
when  the  tube  is  plunged  into  cold  water  ?  and  why  is  the 
piston  moved  up  again,  when  the  bulb  of  the  tube  is  again 
held  over  the  flame  of  the  lamp  ?  What  is  the  cause  of  the 
power  and  operation  of  the  steam-engine  ? 

[§  36.]  What  properties  must  chemically  pure  water 
possess?  When  it  is  only  necessary  to  know  the  propor- 
tion which  the  solid  substances,  dissolved  or  contained  in 
water,  bear  to  the  whole  volume  of  the  liquid,  by  what 
means  may  this  be  ascertained  ? 

[§  37.]  Is  water  the  only  compound  of  oxygen  and 
hydrogen  1  What  other  combination  is  there  of  the  same 
elements  ?  What  is  the  name  of  this  compound  ? 

[§  38.]  What  are  the  principal  properties  of  oxygen- 
ized water  1 

Recapitulate  the  binary  combinations  of  hydrogen  and 
oxygen. 

C.     QUESTIONS  ON  NITROGEN. 

[§  39.]  What  sort  of  gas  is  Nitrogen,  and  what  are 
its  principal  properties  ? 

Why  has  this  gas  been  called  Azote  ?  Is  this  expression 
correct?  Why  not? 


OF    CHAPTER    1.  117 

[§  40.]  By  what  means  may  nitrogen  be  easiest  ob- 
tained ?  How  is  nitrogen  separated  from  oxygen  1 

[§  41.]  What  particular  mixture  of  Nitrogen  and 
Oxygen  resembles,  or  constitutes  our  atmosphere  ? 

How  do  we  know  that  nitrogen  and  oxygen  are  actually 
contained  in  the  atmosphere  in  the  proportion  of  4  volumes 
of  nitrogen  to  1  volume  of  oxygen. 

[§  42.]  Are  nitrogen  and  oxygen  the  only  ingredients 
of  atmospheric  air?  What  other  substances  are  yet  con- 
tained in  it  1  Upon  what  does  the  quantity  of  vapor  de- 
pend 1  Is  the  proportion  of  carbonic  acid  greater  in  sum- 
mer or  in  winter  1  in  the  night  or  in  day-time. 

What  are  the  exact  proportions,  by  weight,  of  nitrogen, 
oxygen,  and  carbonic  acid  gas  contained  in  our  atmosphere, 
abstracting  for  a  moment  from  the  variable  quantity  of  vapor? 

[§  43.]  Is  the  proportion  of  the  principal  ingredients 
of  our  atmosphere,  nitrogen  and  oxygen,  variable  1 

At  what  result  did  Gay  Lussac  arrive  from  examining  the 
air  at  a  height  of  24,600  feet  above  the  level  of  the  sea,  and 
that  of  crowded  theatres  in  Paris  ? 

Has  any  other  mixture  of  gases  been  found  capable  to  sup- 
port the  process  of  respiration  and  animal  life  as  well  as  at- 
mospheric air  ?  What  would  be  the  probable  consequence  if 
the  air  did  contain  more  nitrogen  or  less  oxygen?  What,  on 
the  contrary,  would  take  place  if  the  quantity  of  nitrogen  be 
diminished,  or  that  of  oxygen  increased  ? 

[§  44.]  What  accidental  ingredients  are  yet  contained 
in  the  atmosphere,  besides  those  you  have  already  enumer- 
ated ? 

[§  45.]  What  is  the  object  of  Eudiometry  ?  WThat 
substance  will  answer  this  purpose  ?  What  is  an  appara- 
tus constructed  for  this  purpose  called  1  Explain  the  con- 
struction of  Achard's  Eudiometer  (Fig.  XCV.)  Of  what 
consists  Volta's  Eudiometer  for  detonating  oxygen  and  hy- 
drogen gas  1  (Explain  Fig.  XCVI).  What  other  Eudi- 
ometer may  be  used  for  this  purpose  instead  of  the  ojne 
you  have  just  described  ? 

By  what  means,  in  the  experiment  you  have  now  described, 


118  RECAPITULATION 

are  you  able  to  find  the  volume  of  oxygen  contained  in  atmos- 
pheric air? 

Upon  what  principle  is  Gay  Lussac's  eudiometer  con- 
structed ?  Of  what  does  it  consist  ?  How  is  it  to  be 
used? 

What  fact  has  been  established  by  the  various  experiments 
•which  have  been  made  with  Eudiometers?  Can  the  great 
difference  which  exists  between  the  air  of  certain  places,  and 
at  different  times,  be  explained  from  the  greater  or  less  quan- 
tity of  oxygen  contained  in  it  ?  Do  we  know  anything  about 
the  different  miasmas  which,  at  times,  are  contained  in  the  at- 
mosphere ? 

[§  46.]  In  how  many  different  proportions  does  nitro- 
gen combine  with  oxygen  ?  What  are  the  products  of 
these  combinations  1 

[§  47.]  What  is  the  chemical  composition  of  protox- 
ide of  nitrogen  ?  Is  it  a  product  of  nature  or  of  art  ? 
How  is  it  best  and  easiest  obtained  1  (Explain  the  exper- 
iment represented  in  Fig.  XCVIII). 

[§  48.]  What  are  the  characterizing  properties  of 
protoxide  of  nitrogen. 

What  is  the  average  quantity  of  this  gas  that  can  be  inhaled 
without  being  injurious  to  the  lungs  ? 

What  influence  has  electricity  upon  the  Protoxide  of 
nitrogen  ?  What  becomes  of  this  gas  when  mixed  with 
hydrogen,  and  an  electric  spark  is  applied  to  it  T 

(The  remainder  of  this  section  it  is  sufficient  for  the  pupil  to 
understand.  More  advanced  pupils  may  repeat  the  reasoning.) 

[§  49.]  What  is  the  chemical  composition  of  Deutoxide 
of  Nitrogen  1  By  what  means  is  it  obtained  ?  How  is 
this  process  explained  ? 

[§  50.]  What  are  the  principal  properties  of  deutoxide 
of  nitrogen  ?  What  takes  place  when  deutoxide  of  nitro- 
gen is  mixed  with  oxygen  and  the  experiment  is  made  over 
water?  What  takes  place  if,  instead  of  oxygen,  atmos- 
pheric air  is  employed  ? 

What  instrument  is  founded  upon  the  property  of  the  deu- 
toxide of  nitrogen  to  absorb  the  oxygen  from  atmospheric  air  ? 


OF     CHAPTER  I.  119 

How  then  do  you  use  the  apparatus  described  on  page  92,  Fig. 
XCVII  ? 

[§  51.]  By  what  means  may  deutoxide  of  nitrogen  be 
decomposed  ? 

[$  52.]  What  is  the  supposed  chemical  composition  of 
Hypo-nitrous  acid?  In  what  manner  is  it  generated? 
What  do  some  chemists  pretend,  as  regards  its  appearance 
at  common  temperatures? 

[§  53.]  What  is  the  chemical  composition  of  nitrous 
acid  ?  In  what  way  may  it  be  produced  ? 

[§  54.]  What,  remark  can  you  make  respecting  the 
different  combinations  of  oxygen  and  nitrogen  by  volumes? 
What  general  law  does  this  verify  ? 

[§  55.]     What  are  the  properties  of  nitrous  acid  ? 

[§  56.]  What  is  the  chemical  composition  of  nitric 
acid  ?  Where  is  nitric  acid  found  in  nature  ?  In  what 
way  is  it  obtained  by  art?  By  what  other  means  may  it 
be  procured  ? 

How  is  nitric  acid  produced  in  the  atmosphere  ? 

[§  57.)  Is  nitric  acid,  found  in  either  way  you  have 
just  described,  obtained  in  a  gaseous  or  liquid  state  ? 

[§  58.]  In  what  manner  is  liquid  nitric  acid  prepared 
for  commerce  ?  What  is  the  smallest  quantity  of  water 
with  which1  it  is  known  to  exist?  What  is  the  liquid 
nitric  acid  sometimes  called  ?  When  is  nitric  acid  said  to 
be  in  an  an-hydrous  state  ? 

[$  59.]  What  are  the  characterizing  properties  of 
nitric  acid  ?  What  is  its  specific  gravity  ?  How  does  it 
act  upon  the  skin  and  all  organized  matter  ?  What  takes 
place  when  nitric  acid  is  brought  in  contact  with  hydro- 
gen ?  What  when  poured  upon  warm  powdered  charcoal  ? 
How  does  it  affect  spirit  of  turpentine  or  any  other  essential 
oil?  (Explain  the  experiment  represented  in  Fig.  XCIX.) 

[§  60.]  What  applications  are  made  of  this  acid  in 
the  arts  ? 


120  RECAPITULATION 

[§  61.]  What  is  the  chemical  composition  of  Ammo- 
nia? Where  does  ammonia  occur  ?  How  is  it  best  ob- 
tained ?  What  is  formed  when  the  experiment  is  made 
over  water  ? 

What  is  the  aqueous  solution  of  ammonia  called  ?  What 
does  the  salt  contained  in  smelling-bottles  consist  of? 

[§  62.]     What  are  the  principal  properties  of  ammonia? 
To  what  class  of  bodies  does  ammonia  belong  ?     What  is  it 
therefore  called  ? 

[^  63.]  What  takes  place  when  ammonia  is  passed 
through  red-hot  tubes  (particularly  if  some  iron  wire  be 
coiled  up  in  them)  ? 

What  are  the  most  important  binary  combinations  of 
nitrogen  ? 

D.     QUESTIONS  ON  CHLORINE. 

[§  64.]  In  what  state  is  chlorine  found  in  nature? 
How  may  it  be  produced  by  art  ? 

[§  65  ]  What  are  the  characterizing  properties  of 
chlorine  ? 

In  what  manner  can  chlorine  be  transferred  from  one  vessel 
to  another  ?  (Explain  Fig.  C.)  WThat  other  experiment  can 
be  made  to  show  the  property  of  chlorine  to  support  combus- 
tion and  to  ignite  some  of  the  metals  ? 

[§  G6.]  In  how  many  different  proportions  does  chlo- 
rine combine  with  oxygen  ?  What  are  the  compounds  ? 
Has  any  of  these  compounds  been  found  in  nature  in  its 
simple  state  ?  What  is  the  composition  of  protoxide  of 
chlorine  ?  What  sort  of  gas  is  it  ? 

What  is  the  composition  of  the  peroxide  of  chlorine  ? 
What  are  its  properties  ? 

What  is  the  composition  of  chloric  acid  ?  What  are  its 
properties  ? 

What  is  the  composition  of  per-chloric  acid  ?  What  are 
its  properties  ? 

[§  67.]  What  is  the  name  of  the  compound  formed  by 
the  combination  of  chlorine  with  hydrogen  ?  Where  is 


OF    CHAPTER    1.  121 

this  compound  found  1  What  is  the  composition  of  mu- 
riatic acid  ?  By  what  influence  is  it  obtained  ?  In  what 
other  way  may  muriatic  acid  gas  be  obtained  ? 

[§  63.]  What  are  the  principal  properties  of  muriatic 
acid  1  What  does  muriatic  acid  lose  in  contact  with  the 
oxides  of  metals  ? 

[§  69.]  What  takes  place  when  muriatic  acid  gas  is 
conducted  into  water  ?  What  apparatus  is  generally  em- 
ployed for  this  purpose  ?  (Describe  the  apparatus  repre- 
sented in  Fig.  CI.) 

What  sort  of  vessels  are  employed  when  liquid  muriatic 
acid  is  prepared  on  a  large  scale  ?  What  is  this  the 
cause  of? 

Are  any  applications  of  this  acid  made  in  the  arts  I 
What  are  they  ? 

[§  70.]  To  what  compound  does  chlorine  combine 
with  nitrogen  1  What  is  the  composition  of  this  com- 
pound ?  By  what  process  is  it  formed  ? 

[§  71.]  What  are  the  properties  of  chloride  of  nitro- 
gen ?  How  is  its  great  explosive  power  explained  ? 

What  are  the  principal  binary  combinations  of  Chlorine  ? 


11 


122  CARBON 


CHAPTER    II. 


OP    THE    REMAINING  NINE    NON-METALLIC  ELEMENTS,  AND 

THEIR  COMBINATIONS. 

§  72.  Besides  the  four  gases,  Oxygen,  Hydrogen, 
Nitrogen  and  Chlorine,  there  are  yet  nine  other  non-me- 
tallic elements  which,  with  the  exception  of  Boron,  are  all 
solid  at  the  mean  temperature  of  the  atmosphere.  Their 
names  are  Carbon,  Sulphur,  Selenium,  Phosphorus,  Boron, 
Iodine,  Bromine,  Silicon,  and  Fluor.  They  are,  like  the 
gases,  bad  conductors  of  electricity  and  heat,*  and  become 
all  converted  into  vapor  by  the  application  of  a  gentle 
heat. 

A.     Carbon. 

Chemical  Equivalent  =  6. 

§  73.  Properties  of  Carbon.  Carbon  occurs  in  nature 
as  the  principal  ingredient  of  coal.  It  is  either  found  in 
its  pure  state  —  as  diamond  ;  or  mixed  with  earthy  mass- 
es—  in  graphit,  anthracite  coal,  turf,  &c,  and  enters 
largely  into  the  composition  of  all  animal  and  vegetable 
substances. 

Diamonds  are  chiefly  found  in  the  East  Indies,  (in  the  mines 
of  Golconda)  and  in  Brazil,  (in  the  Province  of  Serro  do  Frio). 
They  are  generally  disseminated  in  sand  or  gravel,  and  fre- 
quently mixed  with  gold.  They  are  considered  gems  of  the 
highest  value.  They  are  found  either  crystallized  (in  form  of 

*  Carbon  is  a  pretty  good  conductor  of  both. 


CARBON.  123 

octahedrons*)  or  in  grains.  They  are  either  colorless,  (and  are 
then  said  to  be  of  the  first  water)  or  of  a  light  red,  green,  blue, 
and  even  black  color.  Diamond  is  the  hardest  substance 
known.  Its  specific  gravity  is  3.5*2.  When  submitted  to  the 
action  of  heat  in  close  vessels  its  properties  do  not  change; 
but  in  the  focus  of  a  large  burning-glass,  or  in  pure  oxygen  it 
is  entirely  consumed.  The  product  of  the  combustion,  car- 
bonic acid  gas,  is  precisely  the  same  as  that  obtained  from 
burning  charcoal. 

Graphit  or  Plumbago  is  of  a  grayish  black  color  (like  iron  or 
steel).  It  is  opaque,  and  has  a  black,  metallic  lustre.  It  re- 
sists the  action  of  a  common  fire,  but  is  consumed  by  higher 
degrees  of  heat,  or  by  the  effect  of  a  voltaic  battery.  It  is  a 
compound  of  carbon  and  about  4  per  cent  of  iron.  Extensive 
use  is  made  of  plumbago  in  the  manufacture  of  lead-pencils. 
It  is  also  used  in  the  making  of  crucibles  for  the  use  of  gold 
and  silver-smiths.  Mixed  with  fat  it  a  most  excellent  means 
to  prevent  friction  in  wagons,  mills,  and  other  machines. 

Anthracite  Coal. —  Anthracite  Coal  (glance-coal  of  the  Eng- 
lish) occurs  in  irregular  forms.  Great  quantities  of  it  are 
found  in  Pennsylvania,  and  will  probably  be  discovered  in  oth- 
er parts  of  the  United  States.  It  is  opaque,  of  a  greyish- 
black  color,  is  rather  difficult  to  kindle,  burns  without  much 
flame  or  smoke,  and  leaves  for  ashes  a  mixture  of  silicious 
earth,  mixed  with  clay  and  oxide  of  iron. 

Lehigh  Coal.  —  Lehigk  Coal  has  a  strong,  metallic  lustre, 
and  leaves  when  burnt  13J  per  cent  white  ashes.  Although 
difficult  to  kindle,  it  is  extensively  used  in  America. 

Black  and  Brown  Coal.  —  Black  and  Brown  Coal  is  found 
in  England  Scotland,f  and  Germany.!  When  burnt  it  oc- 
casions a  disagreeable  smell,  owing  to  the  oily  substances 
which  it  contains,  and  which  are  given  off  during  combustion. 
It  leaves,  however,  but  3  per  cent  of  ashes.  - 

Turf.  —  Turf  is  a  tissue  of  vegetable  substances,  reduced 
to  a  compact  solid,  by  a  peculiar  process  of  decomposition. 
When  slowly  burnt  it  produces  from  26  to  28  per  cent  of  coaZ, 
but  leaves  a  great  deal  of  ashes. 

Vegetable  Charcoal  is  obtained  by  burning  wood,  which  pro- 

*  See  Grand's  Solid  Geometry,  Appendix. 

t  New-Castle,  Whitehaven,Dumfrieshire,  Derbyshire,  Sheffield, 
Clydesdale,  &c. 

|  Silesia,  Westphalia,  Saxony,  Wurtemberg,  and  Bavaria. 


124  CARBON. 

cess,  however,  must  be  carefully  conducted.  It  is  used  as 
fuel  in  cupelling  furnaces ;  as  a  principal  ingredient  in  the 
manufactory  of  powder  (see  Chap.  IV),  and  as  a  dyeing 
stuff  in  the  manufactory  of  blacking.  It  has  the  peculiar 
property  of  resisting  the  putrefaction  of  animal  substances, 
(and  may  therefore  be  used  for  the  preservation  of  meat) ;  but 
it  destroys  their  color  and  smell.  It  is  also  a  great  purifyer  of 
water,  and  is  on  this  account  used  extensively  in  the  refining 
of  sugar.  But  the  most  remarkable  property  of  charcoal  con- 
sists in  its  power  of  resisting  destruction.  This  property 
of  charcoal  was  even  known  to  the  ancients,  who  were  in 
the  habit  of  charring  their  piles  and  posts  (burning  their  sur- 
faces to  coal)  before  driving  them  into  the  ground  ;  and  so 
well  has  this  preserved  them  from  decay,  that  when  the  piles 
upon  which  the  foundation  of  the  temple  of  Ephesus  rested, 
were  but  of  late  taken  from  the  ground,  the  charcoal  upon 
their  surface  appeared  perfectly  fresh,  and  the  wood  under- 
neath free  from  rot  or  putrefaction.  Charcoal  is  also  unalter- 
able by  heat,  if  excluded  from  atmospheric  air;  but  in  contact 
with  other  substances  exercises  a  powerful  influence  upon 
them  by  combining  with  the  oxygen  which  enters  into  their 
chemical  composition.  Its  mechanical  structure  (its  inter- 
stices, or  pores)  enable  it  to  absorb  large  quantities  of  gases, 
and  it  is  known  in  one  instance  to  retain  more  than  90  times 
its  own  volume. 

Animal  Charcoal  (bone-black)  is  obtained  from  burning  an- 
imal substances,  commonly  bones,  horns,  &c.  It  is  of  a  deep 
black  color,  and  is  used  in  the  manufactory  of  printers'  ink. 

REMARK.  —  Although  carbon  abounds  in  all  the  three  king- 
doms of  nature,  it  is  rarely  found  in  its  pure  state  —  as  diamond. 
All  attempts  to  procure  diamonds  by  art,  or,  in  other  words,  to 
extract  pure  solid  carbon  from  other  substances,  have  hitherto 
proved  ineffectual. 

Quen/  — Why  is  charcoal  so  different  in  appearance  from 
diamond,  one  being  black  and  opaque,  the  other  transparent, 
brilliant,  and  the  hardest  substance  known  ?  Jlns.  —  Because 
diamond  is  Carbon  in  its  pure,  crystallized  state,  and  the  other 
is  mixed  with  various  impurities,  and  other  constituents,  adding 
sometimes  more  than  10  or  20  per  cent  to  its  amount  of  pure 
carbon.  Ques.  —  But  why  has  it  thus  far  been  impossible  for 
us  to  crystallize  carbon,  or  to  make  diamonds,  as  we  are  able 
to  produce  water  from  the  union  of  its  ingredients,  hydrogen 
and  oxygen?  Jlns.  —  The  probable  reason  is  that  diamond 
is  of  organic  formation  as  the  similarity  of  its  chemical  com- 


CARBON.  125 

position  to  charcoal  plainly  indicates  ;  and  that  if  this  be  true, 
we  might  as  well  wish  to  create  plants  and  animals,  because 
we  know  their  chemical  composition,  which  would  evidently 
be  impossible. 

Combinations  of  Carbon  with  Oxygen. 

§  74.  Carbon  combines  with  oxygen  in  5  different 
proportions  ;  but  of  the  compounds  thus  formed  there  are 
but  two  which  deserve  special  notice,  or  which  are  of  any 
application  in  common  life.  These  are  carbonic  oxide, 
and  carbonic  acid. 

Carbonic   Oxide 

consists  of  1  equivalent  of  Carbon  =    6 
and  1  equivalent  of  Oxygen  =    8 


Consequently,  chem.  equiv.  of  Carbonic  Oxide  =  14 

§  75.  This  compound  does  not  occur  in  nature ;  but 
is  easily  produced  by  art,  by  applying  heat  to  a  mixture  of 
charcoal  and  lime,  or  by  heating  two  parts  of  chalk  and 
one  of  iron-filings  in  a  gun-barrel,  and  collecting  the  gas 
which  is  given  off  in  the  usual  manner. 

Both  processes  are  easily  explained.  In  the  first  instance, 
the  vapors  of  carbon  produced  by  the  charcoal,  combine  with 
the  oxygen  of  the  lime  (which,  as  we  shall  see,  is  a  combination 
of  oxygen  with  calcium).  In  the  second  case,  when  lime 
or  chalk  are  heated,  carbonic  acid  is  formed  (see  the  next 
section),  which,  when  the  iron  is  heated,  yields  again  a  portion 
of  it  Jo  this  metal;  by  which  means  it  becomes  reduced  to  car- 
bonic oxide. 

§  76.  Properties  of  Carbonic  Oxide.  It  is  a  gaseous, 
colorless  substance,  which  in  its  pure  state  is  without  taste 
or  smell.  It  is  incapable  of  supporting  the  process  of  com- 
bustion, but  is  itself  inflammable  and  burns  with  a  blue 
flame.  When  taken  into  the  lungs  it  causes  giddiness, 
stupor,  and  fainting,  even  when  mixed  with  25  per  cent 
of  atmospheric  air. 

n* 


126 


C  A  R  B  ON  . 


Carbonic  Acid —  (Fixed  Air.) 

Chemical  composition:     1  equivalent  Carbon  =    6 
2  equivalents  Oxygen  (each  8)  =  16 

Consequently,  chem.  equivalent  of  Carbonic  acid  =  22. 

§  77.  Carbonic  acid  gas  is  always  contained  in  small 
quantities  in  the  atmosphere ;  particularly  in  the  neigh- 
borhood of  volcanos  ;  (near  mount  Vesuvius,  in  the  cave 
of  Pausilippo,  near  Puzzuoli,  in  Pyrmont,  &c).  It  is 
continually  produced  by  the  burning  of  wood  or  coal,  by 
the  respiration  of  men  and  animals  (see  chapter  Vll),  and 
by  every  process  of  fermentation  and  putrefaction  which 
takes  place  in  nature.  It  is  also  found  in  coal  mines, 
where  it  occasions  the  chalk  dampness  of  the  miners,  which 
in  many  instances  has  proved  fatal  to  them.  By  art  it  may 
be  produced  by  dropping  fragments  of  marble  or  chalk 
into  dilute  muriatic  or  sulphuric  acid. 

Marble  and  chalk  are  compounds  of  carbonic  acid  with 
an  oxide  of  a  metal  called  oxide  of  calcium,  and  are  com- 
posed of  about  22  parts  of  carbonic  acid  with  28  parts  of 
lime.  When  exposed  to  the  action  of  sulphuric  or  mu- 
riatic acid,  which  have  a  strong  affinity  for  the  lime,  this 
substance  combines  by  elective  affinity  with  the  acid,  set- 
ting the  carbonic  acid  free. 
Fig.  OIL 

For  the  purpose  of 
making  the  experi- 
ment, introduce  some 
pure  white  marble  in 
small  fragments  into 
a  two-necked  bottle  6, 
shaped  like  that  repre- 
sented in  the  adjoining 
figure,  CII.  Upon 
these,  through  the  fun- 
nel n,  pour  some  dilute 
sulphuric  acid  ;  when 
a  quick  effervescence  will  take  place,  by  which  carbonic 
is  given  off  in  abundance,  which  may  be  conducted 


CARBON.  127 

through  the  pipe  P,  through  the   pneumatic   tub  into  the 
receiver  R. 

Query  —  By  what  kind  of  affinity  is  the  carbonic  acid,  in 
this  experiment,  formed  ?  Ans.  —  By  single  elective  affinity. 
Ques.  —  Why  ?  Jins.  —  Because  marble  is  a  carbonate  of 
lime,  consisting  of  a  combination  of  carbonic  acid  with  oxide  of 
calcium  (seethe  last  section);  but  when  sulphuric  acid  is 
added,  for  which  the  oxide  of  calcium  has  a  stronger  affinity 
than  for  carbonic  acid,  then  the  oxide  quits  its  combination 
with  the  carbonic  acid  and  elects  as  it  were,  in  preference,  a 
combination  with  the  sulphuric  acid,  setting  the  carbonic  acid 
free.  This  is  the  cause  of  the  effervescence  which  takes  place 
when  dilute  sulphuric  acid  is  poured  upon  fragments  of  marble 
or  chalk. 

§  78.  Properties  of  Carbonic  Add.  Carbonic  acid 
or  as  it  is  commonly  called,  fixed  air,  is  a  combination 
of  equal  volumes  of  carbon  and  oxygen.  It  is  a  perfectly 
colorless  gas,  which  has  a  pungent,  half  acid  taste,  and  is 
not  inflammable.  A  burning  taper  immersed  in  it  is 
instantly  extinguished.  When  taken  into  the  lungs  it 
proves  speedily  fatal  to  life.  It  is  so  extremely  poisonous 
that  but  a  small  quantity  of  it,  even  mixed  with  atmos- 
pheric air  is  sufficient  to  produce  dimness,  difficulty  of 
respiration,  swoon,  apoplexy,  and  death.  Hence  the  dan- 
ger arising  from  burning  charcoal  in  a  room  that  is  not 
well  ventilated  ;  because  during  combustion  a  considera- 
ble quantity  of  this  gas  is  given  off. 

The  danger  of  burning  charcoal  in  a  confined  room  is  two- 
fold. 1st.  'From  the  fact  that  during  the  process  of  combus- 
tion a  considerable  quantity  of  oxygen  is  consumed,  which, 
if  no  draft  be  created  to  supply  fresh  quantities  of  it,  must 
finally  terminate  in  a  complete  exhaustion  of  that  principle 
which  alone  can  support  animal  life.  2d.  By  the  combination 
of  oxygen  with  charcoal  a  considerable  quantity  of  carbonic 
acid  is  formed,  which  from  the  stupor  and  swoon  which  it 
causes,  deprives  the  person  thus  exposed  to  its  injurious  influ- 
ence, soon  of  the  means  of  rescuing  himself  from  this  deadly 
poison.  It  is  needless  to  dwell  on  the  many  fatal  accidents 
that  have  occurred  either  from  ignorance,  or  from  a  disregard 
of  this  property  of  carbonic  acid. 


128  CARBON. 

§  79.  Carbonic  acid  gas  is  quickly  absorbed  by  water 
and  other  liquids.  In  this  manner  (mechanically  entan- 
gled between  the  particles  of  liquids)  it  is  contained  in  a 
variety  of  mineral  waters,  and  in  all  sparkling,  ferment- 
ing liquors,  such  as  beer,  cider,  champaigne,  &c,  causing 
that  agreeable  pungent  taste,  which  these  liquids  lose 
after  being  for  some  time  exposed  to  the  atmosphere. 
Our  common  Soda  and  Seltzer  waters  are  charged  with 
carbonic  acid  by  means  of  forcing  pumps.  The  pleasant 
fresh  taste  of  common  pump  water  is  in  a  great  meas- 
ure owing  to  the  carbonic  acid  which  collects  at  the  bottom 
of  the  wells.  From  river  water  the  carbonic  acid  is  con- 
tinually absorbed  by  the  atmosphere.  This  constitutes 
the  principal  difference  between  hard  and  soft  water  (see 
Chapter  I,  §  29,  page  71). 

This  is  a  striking  instance  of  the  various  properties  of  gases 
and  their  several  adaptations  to  our  convenience  and  comfort. 
Thus  carbonic  acid,  though  perfectly  irrespirable,  and  poison- 
ous and  destructive  to  life  when  taken  into  the  lungs,  may 
with  impunity  be  taken  into  the  stomach,  and  is  one  of  the 
most  efficient  and  agreeable  means  of  refreshing  ourselves 
when  overcome  by  the  heat  of  summer.  But  what  is  still 
more  interesting  in  this  gas,  is  the  contrast  between  its  prop- 
erties, and  those  of  the  elements  from  which  it  is  derived. 
Carbon,  which  in  the  form  of  charcoal  may  be  taken  into 
the  stomach  in  a  considerable  quantity  without  being  in- 
jurious, and  whose  presence  in  a  dormitory  is  no  more  dan- 
gerous than  atmospheric  air  itself;  when  combined  with  oxy- 
gen, an  element  without  which  life  would  instantly  cease,  and 
which  may  therefore  be  considered  the  very  supporter  of  it, 
forms  a  poison  which  may  destroy  life  in  a  very  few  minutes ! 
And  this  very  poison,  when  taken  into  the  mouth  and  stomach, 
produces  no  other  effect  than  an  agreeable,  gentle  coolness  — 
which  is  perfectly  healthy  and  palatable  ! 


CARBON. 


129 


Fig.  CII1. 

Before  Seltzer  and  soda  waters  became  as 
common  as  they  are  now,  Nooth's  apparatus 
was  used  for  impregnating  water  or  any  other 
liquid  with  carbonic  acid.  Fig.  CHI  shows 
its  construction  and  use.  It  consists  of  a 
vessel  A,  destined  to  hold  some  pulverized 
marble  or  chalk,  upon  which,  through  the 
opening  6,  may  be  poured  some  dilute  sul- 
phuric acid.  The  carbonic  acid  gas  which  is 
thus  generated  ascends  through  the  valve  a, 
into  the  second  vessel  B,  filled  with  the 
liquid,  which  is  to  be  impregnated  with  it. 
The  valve  a,  is  so  constructed  that  it  admits 
the  carbonic  acid  into  the  vessel  B,  but  pre- 
vents the  liquid  in  that  vessel  from  descend- 
ing into  A.  The  uppermost  vessel  C,  is 
destined  to  receive  the  water  which  is  dis- 
placed from  the  vessel  B,  by  the  rise  of  the 
gas.  When  the  liquid  in  B,  is  sufficiently 

charged  with   the    gas,  it  may  be  drawn   off  by  means  of  the 

discharging  cock  D. 

§  80.  It  has  been  mentioned  in  §  36,  page  85,  as  one 
of  the  criterions  of  pure  water,  that  mixed  with  lime-wa- 
ter it  must  not  become  turbid,  otherwise  it  contains  car- 
bonic acid.  The  reason  of  this  is  now  easily  understood. 
When  lime-water  is  poured  into  water  which  contains 
carbonic  acid,  this  substance  combines  immediately  with 
the  lime  to  an  insoluble  compound,  called  carbonate  of 
lime,  which  is  at  first  seen  in  form  of  white  clouds  and 
afterwards  sinks  to  the  bottom. 


hy 


Combination  of  Carbon  with  Hydrogen. 

81.     Carbon  unites  in  two  different  proportions  with 
rogen.     The  products  of  these  combinations  are  two 


permanently  elastic  gases  —  Sub-carburetted  Hydrogen, 
and  Carburetted  Hydrogen. 


130 


CARBON. 


Sub-carburetted  Hydrogen 

is  composed  of  1  equivalent  of  Carbon  =  6 
and  2  equivalents  of  Hydrogen  (each  being  1)  =  2 


Consequently,    chemical  equivalent  of  sub-carbu- 

retted  Hydrogen  =  8. 

§  82.  This  gas,  which  is  also  called  light  Carburetted 
hydrogen,  or  heavy  inflammable  air,  is  formed  wherever  or- 
ganic matter  putrefies,  in  pools,  swamps,  and  stagnant  wa- 
ters. It  is  also  found  in  coal  mines  (the  fire-damp  of  the 
miners),  where  by  its  dreadful  explosion  it  proved  frequent- 
ly fatal  to  the  workmen.  (Disasters  of  this  kind  have 
since  been  obviated  by  Sir  Humphrey  Davy's  safety  lamp, 
for  the  description  of  which  see  the  next  section.) 
Fig.  CIV. 

It  may  be  readily  procured 
by  stirring  the  bottom  of  pools 
or  stagnant  water,  and  collect- 
ing the  gas  which  rises  in  little 
bubbles  with  an  inverted  bottle, 
which  for  this  purpose  ought 
to  be  provided  with  a  funnel, 
(see  the  adjoining  figure,  CIV), 


83.  Properties  of  sub-carbitretted  hydrogen.  It  is 
a  colorless  gas  which  is  highly  inflammable,  and  burns 
with  a  yellowish  blue  flame,  giving  out  considerably  more 
light  than  pure  hydrogen  alone.  But  it  does  not  support 
combustion,  and  is  speedily  fatal  to  animal  life.  Mixed  with 
atmospheric  air  it  forms  a  powerful  explosive  compound, 
which,  on  the  application  of  the  flame  of  a  candle,  detonates 
with  great  violence.  When  burnt  in  oxygen  it  is  decom- 
posed, its  hydrogen  combining  partly  with  the  oxygen  to 


CARBON. 


131 


water,  and  its  carbon  forming  with  the  remaining  oxygen 
carbonic  acid. 

We  have  mentioned  in  §  82  that  light  carburetted  hydrogen 
is  spontaneously  formed  in  coal  mines,  where  by  its  explo- 
sions it  proved  frequently  destructive  to  the  workmen.  This 
is  so  much  more  the  case  as  the  miners  have  no  warning  of  its 
presence  ;  it  being  lighter  than  atmospheric  air,  and  on  that 
account  collects  above  the  ground  on  which  they  work.  To 
this  must  be  added  the  necessity  under  which  miners  are  to 
work  by  the  light  of  lamps,  in  the  immediate  neighborhood  of 
such  an  explosive  compound,  which  frequently  covers  whole 
acres  of  surface,  and  extends  several  hundred  perpendicular 
feet  in  height. 

Now  it  has  been  observed  that  a  high  degree  of  temper- 
ature is  necessary  to  ignite  all  inflammable  mixtures  of 
fases  ;  and  that  metnllic  wire,  even  when  red  hot,  is  insuf- 
cient  for  this  purpose  ;  but  that  the  flame  of  a  candle  will  set 
fire  to  them  ;  because  the  heat  which  is  given  out  by  it,  is  much 
greater  than  that  of  any  red-hot  rnotal.  This  observation,  to- 
gether with  the  discovery  of  Dr  Wollaston,  that  explosive  mix- 
tures cease  to  burn  in  very  narrow  tules,  led  Sir  Humphrey  Davy 
to  suppose  that  if  the  flame  of  a  candle  or  lamp  were  com- 
pletely surrounded  by  wire-gauze,  consisting  of  very  fine 
meshes,  it  would  perhaps  protect  the  gas  from  being  ignited, 
and  yet  afford,  through  the  small  apertures  of  the  gauze,  suffi- 
cient light  for  the  miners  to  work  by.  This  idea  was  most 
completely  realized  by  the  invention  of  his  safety  lamp  ;  which 
is  now  generally  used  by  miners,  and  by  which  thousands  of 
lives  are  annually  protected  against  the  consequences  which 
might  attend  explosions  in  coal  mines. 

Fig.  C.V. 

It  consists  of  a  cistern  C,  containing 
all  that  is  necessary  for  a  common  lamp, 
and  having  a  spout  D,  on  its  side  for  the 
purpose  of  feeding  it  with  oil.  The 
flame  of  the  lamp  is  covered  by  a  cylin- 
der of  wire-gauze,  which  is  supported 
by  three  brass  rods,  to  which  is  fixed  the 
cover,  and  a  ring  or  handle  by  which  the 
whole  is  carried.  A  represents  a  piece 
of  wire  which  moves  up  and  down  in  a 
tube,  and  by  which  the  lamp  is  trimmed 
without  establishing  a  direct  communi- 
cation between  it  and  the  external  air. 
This  lamp,  upon  experiment,  has  been 
found  to  answer  all  the  purposes  for 
which  it  was  intended,  and  may  be  car- 
ried with  perfect  safety  into  the  most 


132 


CARBON. 


explosive  mixtures  of  gases,  even  when  the  wire-gauze  has 
become  red-hot  by  heat  —  for  the  gas  will  not  be  ignited  by  it. 

Query  —  What  is  the  reason  the  flame  does  not  pass 
through  the  wire-gauze  of  Sir  Humphrey  Davy's  safety- 
lamp  ?  Jlns.  —  Because  the  meshes  of  which  it  consists  act 
as  so  many  narrow  tubes  through  which  (according  to  Dr 
Wollaston's  experiments)  the  flame  of  the  lamp  does  not  pass  ; 
and  the  red-hot  wire,  of  itself,  is  not  sufficient  to  ignite  it. 
Ques.  —  But  what  is  the  reason  the  flame  does  not  pass  through 
the  wire-gauze  ?  JIns.  —  Because  the  flame  coming  in  con- 
tact with  the  wire,  which  is  a  good  conductor,  its  heat  becomes 
latent  or  hidden  (Natural  Philosophy,  Chap.  VI),  which  reduces 
its  temperature  below  that  which  is  necessary  to  ignite  gas.* 

That  wire-gauze  does  completely  intercept  the  flame  of  any 
burning  substance,  may  yet  be  shown  by  the  following  easy 

EXPERIMENT.  —  Provide  a  bottle  filled  with  hydrogen  gas  ; 
Fig.  CVI. 


through  its  neck  introduce  a  narrow  pipe,  and  ignite  the  gas 
which  will  escape  through  the  rnouth  of  the  pipe  (see  experi- 
ment, Fig.  LXXXIII,  page  69).  If  a  piece  of  wire-gauze  is 
held  over  the  flame,  as  represented  in  A,  the  flame  will  be  flat- 
tened down,  but  it  will  not  pass  through  the  gauze  ;  if  on  the 
contrary  the  gas  is  ignited  above  the  gauze,  as  represented  in 
Fig.  B,  then  it  will  indeed  burn  freely  ;  but  the  flame  will  not 
be  communicated  to  the  pipe.  This  serves  to  explain  the  op- 
eration and  usefulness  of  the  safety-lamp. 

*  The  learner  ought  to  recollect  that  the  flame  of  a  lamp  or  candle 
consists  of  burning  gas  or  vapors  (see  Fig.  LXII  and  LXIII,  Chap. 
I,  page  53> 


CARBON.  133 

Carburetted  Hydrogen  —  Olefiant  gas. 

Chemical  Composition  :     2  equivalents  of  carbon, 

(each  =  6)  =  12 
2  equivalents  of  Hydrogen  (each  =  1)=    2 


Chemical  equivalent  of  Carburetted  Hydrogen  =  14. 

§  84.  This  compound  is  altogether  a  product  of  art.  It 
may  be  obtained  by  dry  distillation  of  animal  or  vegetable 
substances,  or  from  a  mixture  of  one  volume  of  alcohol  and 
four  volumes  of  strong  sulphuric  acid,  gently  heated  in  a 
retort.  The  mixture  will  soon  turn  black,  and  emit  the  gas. 
which  may  be  collected  over  water  as  in  the  usual  way. 

Alcohol  is  a  compound  of  carbon,  hydrogen,  and  oxygen, 
as  we  shall  see  in  the  7th  Chapter,  when  treating  on  vege- 
table chemistry  ;  but  when  sulphuric  acid  is  added,  which  has 
a  great  affinity  for  water,  (contained  in  the  alcohol),  it  sets  the 
carbon  and  part  of  the  hydrogen  free,  which  combine  with 
each  other,  to  olefiant  gas. 

§  85.  Properties  of  Carburetted  Hydrogen,  or  Oleji- 
ant  Gas.  It  is  a  perfectly  colorless,  elastic  fluid,  of  a  disa- 
greeable smell,  (but  no  taste)  which  is  easily  inflammable 
and  burns  with  a  yellowish  white  flame,  much  brighter 
than  the  common  flame  of  a  taper.  When  mixed  with 
oxygen  and  ignited,  it  detonates  with  great  violence.  By 
passing  it  through  a  red-hot  porcelain  tube,  it  parts  with  a 
portion  of  its  carbon,  by  which  means  it  becomes  con- 
verted into  sub-carburetted  hydrogen  (see  §  82). 

§  86.  Applications  of  the  Olefant  Gas.  The  flame 
of  pure  Carburetted  hydrogen  gas  gives,  as  we  have 
said  before,  a  most  brilliant  light,  and  is  on  that  account 
extensively  used  for  illuminating  shops  and  streets  instead 
of  lamps  and  candles. 

The  brilliancy  of  the  flames  of  other  gases  depends  on  the 
quantity  of  olefiant  gas  which  enters  into  their  composition, 
or,  in  general,  upon  the  quantity  of  carbon  which  they  contain  ; 
the  light  which  they  give  out  being  always  in  proportion  to  that 
substance.  Diamond,  which  is  pure  carbon,  when  burnt  in 
oxygen  gas  or  by  the  agency  of  a  powerful  galvanic  battery, 
throws  out  so  vivid  a  light,  that  if  the  experiment  be  made  by 
12 


134  CARBON. 

candle-light,  the  very  flame  of  the  candles  will  yet  appear 
casting  a  shadow  on  the  wall. 

Gas-light  was  employed  for  illumination,  as  long  as  a 
century  ago,  by  Dr  Clayton  ;  but  for  its  general  introduc- 
tion we  are  indebted  to  Mr  Murdock  who  first  intro- 
duced it  into  England,  from  which  it  gradually  spread  all 
over  the  continent  of  Europe,  and  is  now  successfully  em- 
ployed in  some  of  the  large  cities  of  America.  That  used 
in  Europe  for  illuminating  shops  and  streets,  is  generally 
prepared  from  bituminous  coal  distilled  in  close  vessels  at 
a  red  heat.  Oil  and  resin  have  lately  been  employed  with 
the  same  good  effect.  In  America  olefiant  gas  is  prepar- 
ed principally  from  the  distillation  of  whale  oil.  This  is 
done  in  large  retorts,  half  filled  with  pieces  of  brick  to 
increase  the  heated  surface.  The  oil  is  by  this  means  de- 
composed and  yields  a  large  quantity  of  gas,  which  is 
much  purer,  and  contains  a  greater  proportion  of  carburet- 
ted  hydrogen  than  that  which  is  prepared  from  coal.  It  is 
on  that  account  better  adapted  to  the  purposes  of  illumin- 
ation than  coal-gas  ;  but  its  preparation  is  much  more  ex- 
pensive. Resin,  by  a  peculiar  treatment  has  been  dis- 
covered to  yield  the  same  gas  at  only  one  fourth  of  the 
expense  of  the  gas  prepared  from  oil,  and  is  now  much 
employed  in  the  shops  of  London  and  Paris.  The  gas 
which  is  thus  obtained  is  conducted  in  pipes  to  the  place 
where  it  is  to  be  burned. 

The  reason  why  carburetted  hydrogen  has  also  been  called 
olefiant  gas,  is  because  it  readily  combines  with  chlorine  to  a 
yellowish  liquid  resembling  oil. 

Besides  carburetted  and  sub-carburetted  hydrogen,  there 
exist  yet  a  number  of  other  combinations  between  hydrogen 
and  carbon,  the  precise  composition  of  which  has  not  as  yet 
been  ascertained. 

Combination  of  Carbon  with  Nitrogen  —  Cyanogen. 
Chemical  composition  of  Cyanogen. 

2  equivalents  of  Carbon  (each  =  6)  =  12 
1  equivalent  of  nitrogen  =  14 

Consequently,  chemical  equivalent  of  Cyanogen  =  26. 
§  87.     Carbon  combines  with  nitrogen  and  forms  with 


CARBON.  135 

it  a  gas,  which  is  called  carburet  of  nitrogen  or  cyanogen 
This  gas  does  not  occur  in  nature  ;  but  may  be  obtained 
by  art,  by  boiling  a  substance  called  Prussian  blue  with  red 
oxide  of  quicksilver  in  a  sufficient  quantity  of  water.  By 
this  means  a  compound  is  obtained,  which  upon  cool- 
ing shoots  into  crystals,  and  is  called  cyanuret  of  mercury. 
This  substance  when  dried  at  a  temperature  a  little  below 
the  boiling  point,  and  afterwards  in  a  retort  exposed  to  a 
gentle  heat,  becomes  dark  and  liquid,  and  gives  off  a  gas 
which  may  be  collected  over  quicksilver.  This  gas  is  the 
carburet  of  nitrogen,  or  cyanogen. 

§  88.  Properties  of  Cyanogen.  It  is  a  colorless,  in- 
flammable gas,  which  has  a  pungent  smell  and  affects  the 
eyes.  Its  most  remarkable  property  consists  in  its  capa- 
city to  combine  with  other  substances  in  a  manner  similar 
to  oxygen,  although  it  is  a  compound,  and  oxygen  is  an 
element.  On  this  account  it  has  been  called  cyanogen,  an 
appellation  resembling  that  of  other  elements  (hydrogen, 
oxygen,  nitrogen,  &,c.)  from  two  Greek  words  signifying 
'  formation  of  blue/  because  it  is  a  principal  ingredient  of 
Prussian  blue.  On  this  account  we  shall  make  an  exception 
to  the  general  principle  laid  down  in  the  plan  of  this  trea- 
tise, —  to  treat  in  the  first  three  chapters  only  of  the  ele- 
ments and  their  binary  compounds  —  and  proceed  imme- 
diately with  the 

Combinations  of  Cyanogen  with  Oxygen. 

§  89.  Cyanogen  combines  with  oxygen  in  three  dif- 
ferent proportions,  forming  with  it  three  different  com- 
pounds, viz  :  Cyamms  acidjfulminic  acid,  and  cyanic  acid. 
All  these  substances  are  products  of  art  (the  latter  has 
only  been  discovered  in  1828)  and  may  be  obtained  indi- 
rectly from  the  action  of  alcohol  on  some  of  the  salts  called 
nitrates.  (See  Chap.  IV).  Their  chemical  composition 
is  not  yet  satisfactorily  determined. 

Combination  of  Cyanogen  witli  Hydrogen  —  Prussic  Acid. 

Chemical  composition :     1  equivalent  of  Cyanogen  =  26 
1         do.  Hydrogen  =    I 

Chemical  equivalent  of  Prussic  acid  =  27 


136  CARBON. 

§  90.  A  combination  of  Cyanogen  with  hydrogen  is 
called  hydro-cyanic  or  Prussic  acid.  This  acid  is  contain- 
ed, and  may  be  extracted  from  many  vegetables,  particular- 
ly from  bitter  almonds,  from  the  stones  of  peaches,  prunes, 
cherries,  &c  ;  in  short  from  all  vegetable  substances  which 
smell  like  bitter  almonds.  But  it  may  also  be  obtained 
from  Prussian  blue,  by  the  following  complicated  process  : 
Mix  together  4  ounces  of  powdered  Prussian  blue,  2^- 
ounces  of  red  oxide  of  mercury,  and  about  12  ounces  of 
water ;  boil  the  mixture  half  an  hour,  and  stir  it  frequently 
during  that  time.  When  the  blue  color  of  the  mixture  has 
disappeared  and  changed  into  a  yellowish  green,  filter  the 
solution,  and  add  to  the  residue  a  sufficient  quantity  of  boil- 
ing water  to  make  up  for  the  loss  by  the  first  boiling.  When 
this  solution  is  again  filtered,  put  it  into  a  tubulated  retort  r, 

Fig.  CVII.  (see  tlie  figure)»  containing 

2  ounces  of  iron  filings,  and 
pour  upon  it,  through  the 
opening  b,  3  or  4  ounces  of 
dilute  sulphuric  acid.  Con- 
nect the  retort  now  with  a 
receiver  a,  and  apply  to  it 
the  flame  of  a  lamp.  Va- 
pors of  Prussic  acid  will 
be  formed  in  the  retort  r, 
which  may  be  condensed  in 
the  receiver  a,  by  covering 
it  with  a  wet  cloth,  for  the 
purpose  of  keeping  it  cool 
and  secluding  it  from  the 
light.  The  distillation  may 
be  continued  until  about 
three  ounces  of  Prussic  acid 
are  obtained. 

The  generation  of  Prussic  acid  by  the  process  we  have 
just  described  is  accounted  for  in  the  following  manner. 
Prussian  blue  is  a  combination  of  Prussic  acid  with  iron  ; 
but  when  the  red  oxide  of  mercury  is  added,  for  which 
the  Prussic  acid  has  a  stronger  affinity  than  for  iron,  it 
quits  its  combination  with  this  substance  and  unites  with 


CARBON.  137 

the  oxide  of  mercury  to  a  salt  called  Prussiate  of  Mercu- 
ry, which  is  immediately  dissolved  by  the  boiling  water. 
When  the  iron-filings  and  the  sulphuric  acid  are  added  to 
this  solution,  the  iron  combines  with  the  oxygen  of  the 
oxide  of  mercury,  setting  the  mercury  free,  which  is  pre- 
cipitated to  the  bottom,  while  the  oxide  of  iron  which  is 
thus  formed,  combines  with  the  sulphuric  acid  to  another 
salt,  which  is  called  Sulphate  of  Iron.  The  Prussic  acid, 
which  by  this  means  becomes  completely  disengaged  from 
its  new  combination  with  mercury,  is  by  the  heat  of  the 
lamp  volatilized,  and  passes  in  form  of  vapors  into  the  re- 
ceiver, where,  in  contact  with  the  cold  glass,  it  is  again 
condensed  into  the  liquid  form. 

§  91.  Properties  of  Prussic,  or  hydro-cyanic  acid.  It  is 
a  clear,  colorless  liquid  ;  has  a  strong  (somewhat  penetra- 
ting) smell,  resembling  that  of  peach  blossoms,  and  when 
strongly  diluted  with  water,  has  a  cooling,  pungent  taste, 
like  bitter  almonds.  In  its  pure  state  it  is  the  most  pow- 
erful poison  in  nature.  A  few  drops  placed  on  the  tongue 
of  a  small  animal  causes  its  death  in  a  very  few  seconds. 
An  elephant  was  killed  by  a  hundred  drops  of  it,  and  Prof. 
Wahring,  of  Vienna,  died  by  diffusing  a  small  quantity  of 
it  on  his  naked  arm.  The  vapors  of  this  gas  are  inflam- 
mable, and  when  mixed  with  oxygen,  detonate  on  the  ap- 
plication of  an  electric  spark.  It  boils  at  a  temperature 
of  about  80  degrees  Fahrenheit,  and  congeals  a  little  be- 
low zero.  Diluted  with  water  it  is  employed  in  medicine  ; 
—  and  it  is  also  used  in  the  dyeing  of  broadcloths. 

It  is  liable  to  spontaneous  decomposition  into  its  ele- 
ments, which  seem  to  have  but  a  feeble  affinity  for  each 
other,  and  is  on  this  account,  difficult  to  preserve,  even  in 
close  vessels  arid  secluded  from  the  light  of  day. 

The  first  stage  of  its  decomposition  is  marked  by  the 
liquid  assuming  a  brown  color,  which  soon  turns  into 
black  and  deposites  a  dark  sediment.  When  arrived  at 
this  stage  it  loses  its  peculiar  smell  and  emits  that  of  am- 
monia (see  §  62,  page  102).  It  is  then  no  longer  a  poison 
and  has  lost  all  its  characterising  properties 

§  92.     Prussic  acid  differs  from  the  acids  we  have  thus 
far  become  acquainted  with,  in  the  following  properties  : 
12* 


138  CARBON. 

1st.  In  its  chemical  composition  ;  it  being  a  combina- 
tion of  three  elements,  (nitrogen,  carbon,  and  hydrogen) 
without  oxygen,  and 

2d.  By  its  possessing  the  acid  qualities  in  a  very  feeble 
degree  ;  for  it  has  neither  a  sour  taste,  nor  does  it  redden 
litmus  paper ; 

But  in  combination  with  those  substances  called  bases 
it  forms,  as  we  shall  see,  salts  like  the  rest  of  the  acids 
(see  Introduction,  page  38) ;  and  when  separated  from 
these  again  by  the  agency  of  galvanic  electricity,  it  ad- 
heres to  the  positive  pole  —  showing  thereby  that  it  is  a 
negative  electric.  (Compare  what  we  have  said  in  the 
Introduction,  page  38,  with  regard  to  the  nature  of  acids). 

When  a  quantity  of  potassium  sufficient  to  absorb  50 
measures  of  cyanogen  is  heated  with  100  measures  of  vapors 
of  Prussic  acid,  the  50  measures  of  cyanogen  are  wholly  ab- 
sorbed, and  nothing  but  50  measures  of  pure  hydrogen  remain  ; 
which  proves  that  Prussic  acid  is  composed  of  equal  volumes  of 
cyanogen  and  hydrogen.  But  as  the  cyanogen  is  about  26 
times  heavier  than  hydrogen  (its  specific  gravity  being  nearly 
26  times  that  of  hydrogen),  it  follows  that  its  composition,  by 
weight  is  1  equivalent  of  hydrogen  to  26  of  cyanogen,  as  sta- 
ed  at  the  head  of  the  87th  section. 

Other  Combinations  of  Cyanogen. 

§  93.  Cyanogen  combines  yet  with  Chlorine  in  two 
proportions,  forming  with  it  Proto-chloride  and  per-chlo- 
ride  of  Cyanogen.  In  a  similar  manner  does  it  combine 
with  the  two  elements  Iodine  and  Bromine..  All  these 
substances  have  similar  properties ;  they  are  possessed  of 
a  peculiar,  irritating  odor,  and  are  active  poisons. 

A  compound  of  cyanogen  and  sulphur  is  called  sulphu- 
retted cyanogen.  It  is  colorless,  has  a  pungent  smell,  and 
reddens  litmus  paper. 

Combinations  of  Carbon  with  Chlorine. 

§  94.  Carbon  and  chlorine  combine  with  each  other 
in  three  different  proportions,  forming  sub-chloride,  chlo- 
ridej  and  per-chloridc  of  carbon.  All  these  combinations 
are  mere  products  of  art,  and  are  as  yet  little  employed  in 
the  arts. 


CARBON.  139 

Combination    of    Carbon    with  Sulphur  —  Sulphuret   of 
Carbon. 

Chemical  composition  :     1  equivalent   of  Carbon  =    6 
2  equivalents  of  sulphur  (each  being  16)  =  32 


Consequently,  chem.  equiv.  of  Sulphuret  of  Carbon  =  38. 

§  95.  Carbon  and  sulphur  may  be  made  to  combine 
by  the  following  process,  described  in  the  Library  of  Use- 
ful Knowledge.  Place  an  earthen  tube  of  about  an  inch 

Fig.  CVJII. 


and  a  half  in  diameter,  a  little  inclined  across  a  charing 
dish,  and  fill  it  nearly  with  small  pieces  of  charcoal,  well 
burnt  and  quite  free  from  moisture.  To  the  higher  end  of 
this  tube  adapt  a  glass  tube  filled  with  small  pieces  of  sul- 
phur, which  may  be  pushed  forward  by  means  of  a  wire 
passing  air-tight  through  a  cork.  To  the  other  end  of  the 
earthen  tube,  a  bent  glass  tube  must  be  adjusted,  which 
must  pass  below  the  surface  of  some  water  contained  in  a 
bottle.  When  the  fire  in  the  chafing  dish  has  been  light- 
ed, and  the  centre  of  the  tube  become  red-hot,  the  sul- 
phur in  th'e  glass  tube  must  be  pushed  forward  to  come 
in  contact  with  the  ignited  charcoal,  and  immediately  bub- 
bles of  gas  will  escape  from  under  the  water  into  the  bottle, 
and  a  vapor  will  appear,  which  will  condense  under  the 
water  into  a  liquid.  This  is  sulphuret  of  carbon  —  mixed 
however  with  a  portion  of  water,  from  which,  and  other 
impurities,  it  may  be  freed  by  distilling  it  over  at  a  gentle 
heat  (not  exceeding  110  degrees  Fahrenheit),  in  a  retort 
containing  a  little^ chloride  of  calcium,  a  substance  which 
absorbs  water  very  rapidly. 

§  96.     Properties    of  Sulphuret  of  Carbon.     It   is   a 
colorless,  transparent  liquid,  has  a  strong  acid  (not  acrid) 


140 


CARBON. 


taste,  a  nauseous,  fetid  smell,  and  is  so  exceedingly  volatile 
as  to  boil  already  at  a  temperature  of  1 10  degrees  Fahren- 
heit. Its  boiling  point,  therefore,  is  102  degrees  below  that 
of  water.  This  is  the  reason  why  in  distilling  it  over,  the 
heat  applied  to  it  must  not  exceed  1 10  degrees  Fahrenheit. 
No  degree  of  artificial  cold  has  ever  made  it  congeal ;  but 
it  is  highly  inflammable,  and  emits  during  its  combustion 
copious  fumes  of  sulphuric  acid  (owing  to  its  decomposition, 
in  consequence  of  which  the  sulphur  combines  with  the 
oxygen  of  the  atmosphere  to  sulphuric  acid).  It  is 
heavier  than  water,  its  specific  gravity  being  1 .27,  that  of 
water  being  1  ;  which  is  the  reason  why  it  falls  to  the  bot- 
tom when  poured  into  water.  Owing  to  its  great  volatility 
it  is  a  highly  refrigerating  substance.  A  thermometer 
whose  bulb  is  covered  with  lint  that  has  been  moistened 
with  sulphuret  of  carbon,  will  rapidly  fall  to  zero.  Under 
the  receiver  of  an  air-pump  (when  the  pressure  of  atmos- 
pheric air  is  removed)  it  is  capable  of  causing  even  quick- 
silver to  freeze. 

Recapitulation  of  tlw,  principal  binary  and  ternary  Com- 
binations of  Carbon. 


Carbon 
combines 
with 


Nitrogen  to 

Cyanogen, 

which  com- 


bines  again 
with 


C  cyanous  } 
oxygen  tolfulminic  >acid. 

(  cyanic  ^ 
hydrogen  to  Prussic  acid. 


.  protochlo-    . 
chlorine  to  {  ride  ^ot  Cyan- 

(per-chlorideY gen- 
sulphur  to  sulphuretted  cyanogen. 
C  sub-chloride   ^ 
Chlorine  to  <  chloride          >  of  Carbon. 

( per-chloride    ) 
Sulphur  to  sulphuret  of  carbon. 


SULPHUR. 


141 


B.     Sulphur. 

Chemical    Equivalent  =  16. 

§  97.  Sulphur  is  one  of  the  few  elements  which  occur 
in  their  simple  form,  and  abound  in  all  the  three  kingdoms 
of  nature,  but  it  is  particularly  found  in  the  vicinity  of  vol- 
canos,  and  in  mountains  of  quartz  and  gypsum. 

It  has  been  discovered  in  the  sulphur  mountains  of  Ticsan 
near  Quito  ;  in  the  valley  of  Noto  and  Mazzara  ;  on  the  banks 
of  the  Salso  in  Sicily  ;  in  Spain  ;  in  Poland  (near  Krakau) ;  in 
Auvergne,  near  Mount  Vesuvius,  and  in  a  crystallized  state 
(sofatora)  near  Puzuoli  in  the  kingdom  of  Naples  and  in  the 
neighborhood  of  Mount  JEtna,  in  Iceland,  in  Teneriffe,  Guada- 
loupe,  Java,  and  the  Island  of  Bourbon.  The  volcano  Purace, 
in  South  America,  covers  its  immediate  vicinity  with  crusts 
of  sulphur. 

Sulphur  is  also  contained  in  many  plants,  especially  in 
mustard,  onions,    and  garlic,  and  in   many  animal   sub- 
stances, especially  in  the  eggs  of  fowls. 
Fig.  CIX. 

To  purify  it  from  stones  and  oth- 
er earthy  substances,  it  is  melted 
and  distilled  (sublimed).  For  this 
purpose  a  heat  of  about  500  de- 
grees Fahrenheit  may  be  applied 
to  some  sulphur  in  a  retort.  It 
will  first  melt  and  then  be  changed 
into  vapors,  which  when  coming 
in  contact  with  the  colder  receiver 
are  condensed  again  and  adhere  to 
the  sides  of  the  glass  in  form  of  a 
fine  powder  called  jlour  of  sulphur. 
The  properties  of  this  powder  are 
yet  the  same  as  that  of  sulphur. 


1 42  SULPHUR. 

§  98.  Propertiesof  Sulphur.  Sulphur  is  a  greenish-yel- 
low, tasteless  mineral ;  which  is  highly  inflammable,  burns 
with  a  faint  blue  light,  and  emits  when  rubbed,  or  during 
combustion,  a  peculiar  suffocating  odor.  The  heat  which 
it  throws  out  is  so  small  that  it  may  be  burnt  out  of  gun- 
powder, of  which  it  is  a  principal  ingredient,  without  ignit- 
ing it.  Its  specific  gravity  is  1.92  (water  being  1),  and  it 
is  therefore  nearly  twice  as  heavy  as  water.  At  the  tem- 
perature a  little  above  the  boiling  point  of  water  it  be- 
comes liquid,  and  is  then  cast  into  moulds  and  sold  in 
commerce  under  the  name  of  roll-brimstone.  When  in  a 
state  of  fusion  it  is  poured  into  water  it  becomes  of  a 
consistency  like  wax,  and  is  then  used  for  taking  impres- 
sions of  coins,  medals,  cameos,  &c,  for  which  purpose  it 
is  particularly  adapted  ;  because  its  color,  when  fused, 
changes  into  brown,  and  resembles  that  of  bronze.  The 
applications  of  sulphur  are  numerous.  It  is  used  for 
matches ;  in  the  manufactory  of  gun-powder  (of  which  ii, 
forms  a  principal  ingredient),  in  the  preparation  of  sul- 
phuric acid,  of  cinnabar,  of  blue  vitriol,  &,c.  and  it  is  also 
extensively  employed  in  medicine. 

Combination  of  Sulphur  with  Oxygen. 

§  99.  Sulphur  combines  with  oxygen  in  four  differ- 
ent proportions  ;  in  the  proportion  of  1  to  1 ,  1  to  2,  2  to 
5,  and  1  to  3  equivalents,  forming  with  it  hypo-sulphurous 
acid,  sulphurous  add,  hypo-sulphuric  acid,  and  sulphuric 
acid.  The  first  and  third  of  these  combinations  are  pro- 
ducts of  art,  and  of  little  use  in  common  life  ;  but  the 
second  and  fourth  are  highly  important  to  the  manufac- 
turer and  the  physician.  We  shall  therefore  treat  only 
of  sulphurous  and  sulphuric  acid. 

Sulphurous   Acid 

is  composed  of  1  equivalent  of  sulphur  =  16 
and  2  equivalents  of  oxygen  (each  8)  =  16 

Consequently,  chem.  equiv.  of  sulphurous  acid  =  32. 

§  100.  This  compound  is,  in]a  gaseous  form,  contained 
in  the  atmosphere  in  the  vicinity  of  volcanos.  It  is  also 


SULPHUR.  143 

found  (absorbed)  in  water  :  but  may  be  obtained  also  by 
burning  sulphur  in  atmospheric  air.  It  may  also  be  pro- 
duced in  a  state  of  great  purity  by  the  action  of  sulphuric 
acid  (for  the  preparation  of  which  see  the  following  sec- 
tion) on  mercury.  A  mixture  of  these  two  substances 
may  be  gently  heated  in  a  retort,  and  the  gas  which  will 
be  given  off  collected  over  mercury — water  having  too 
great  an  affinity  for  it. 

This  process  is  easily  explained  in  the  following  manner : 
sulphuric  acid  is  a  compound  of  1  equivalent  of  sulphur  with 
three  of  oxygen.  When  this  is  heated  with  mercury  for  which 
its  oxygen  has  a  great  affinity,  one  equivalent  of  oxygen  com- 
bines with  the  metal,  and  the  two  equivalents  of  oxygen  which 
remain  united  with  the  sulphur,  form  sulphurous  acid  gas. 

§  101.  Properties  of  Sulphurous  Add.  It  is  a  col- 
orless, transparent  gas,  which  possesses  a  peculiar  smell 
and  extinguishes  all  burning  bodies.  It  is  itself  incom- 
bustible, and  when  taken  into  the  lungs  causes  coughing 
and  suffocation.  By  a  pressure  of  30  pounds  to  the  square 
inch,  it  becomes  liquefied.  It  is  speedily  absorbed  by  water, 
which  is  capable  of  absorbing  more  than  33  times  its  own 
bulk  of  it,  and  forms  with  it  what  is  properly  called  liquid 
sulphurous  acid;  but  it  cannot  in  this  state  be  preserved 
for  any  length  of  time. 

All  vegetable  colors,  with  the  exception  of  cochineal, 
are  destroyed  by  it.  (Blue  vegetable  colors  are  first  turn- 
ed into  red  and  then  wholly  discharged  ;  cochineal  is 
only  turned  lighter,  and  changes  into  a  yellowish  red.)  It 
is  extensively  used  in  bleaching,  especially  for  silk  and 
straw  ware. 

Sulphuric  Acid —  (Oil  of    Vitriol). 

Chemical  composition  :     1  equivalent  of  Sulphur  =  16 
3  equivalents  of  Oxygen  (each  =  8)  =  24 


Chemical  equivalent  of  sulphuric  acid  =  40. 

§  102.  Sulphuric  acid  is  the  highest  degree  of  oxy- 
genation  of  which  sulphur  is  capable.  It  occurs  in  nature 
diluted  with  water  in  the  Rio  Vinagre,  in  South  America; 
in  the  Indian  Lake  at  Java,  and  in  Italy,  and  is  of  all  the 


144  SULPHUR. 

acids  the  most  important  to  the  arts.  It  is  therefore  man- 
ufactured in  great  quantities,  and  forms  an  important  arti- 
cle of  commerce. 

In  commerce  there  are  two  sorts  of  sulphuric  acid, 
Hydro-sulphuric  acid,  or  oil  of  vitriol,  and  sulphuric  acid 
properly  speaking.  The  first  is  obtained  from  a  substance 
called  green  vitriol  of  iron,  and  the  second  from  burning 
saltpetre  with  sulphur. 

The  process  by  which  the  oil  of  vitriol  is  procured  is  the 
following  :  Green  vitriol,  copperas,  or  as  it  is  properly  called, 
sulphate  of  iron  (because  it  is  composed  of  sulphuric  acid  and 
protoxide  of  iron)  is  distilled  at  a  high  heat,  by  which  means  it 
becomes  decomposed,  and  a  dense,  oily,  colorless  liquid  is  ob- 
tained, which  in  contact  with  the  atmosphere  emits  copious 
white  vapors.  This  liquid  is  afterwards  again  distilled  at  a 
lower  temperature,  and  made  to  pass  into  a  receiver  surrounded 
with  ice,  where  it  forms  transparent,  colorless  vapors,  which 
condense  into  a  white,  crystalline  solid.  This  is  supposed  to 
be  the  sulphuric  acid  in  an  an-hydrous  state  (without  water), 
and  the  residue  in  the  retort,  which  is  now  no  longer  fuming, 
is  the  common  oil  of  vitriol  as  it  occurs  in  commerce.  The 
solid  substance  liquefies  again  at  a  temperature  a  little  above 
60  degrees  Fahrenheit,  and  has  so  strong  an  affinity  for  water, 
that  it  absorbs  it  from  the  atmosphere  as  soon  as  it  is  brought 
in  contact  with  it. 

Hydro-sulphuric  acid  (sulphuric  acid  dissolved  in  water) 
which  is  the  sulphuric  acid  of  commerce,  is  manufactured  in 
large  quantities  by  burning  a  mixture  of  8  parts  of  sulphur 
and  1  of  nitre  in  close  leaden  chambers,  containing  at  the  bot- 
tom a  small  sheet  of  water.  During  combustion  fumes  of 
sulphuric  acid  rise  and  are  absorbed  by  the  water  ;  from  which 
the  acid  is  afterwards  obtained  in  a  concentrated  state  by 
evaporating  the  solution.  The  theory  of  this  process  is  some- 
what complicated,  and  will  be  best  understood  from  the  fol  • 
lowing  table. 


SULPHUR. 


145 


Liquid 
sulphuric  acid. 


146  SULPHUR. 

Nitre  is  a  compound  of  oxide  of  potassium  with  nitric  acid, 
which,  as  we  know,  is  composed  of  nitrogen  and  oxygen  (§  56, 
page  99).  Now  when  sulphur  is  burnt  with  nitre  in  chambers 
containing  atmospheric  air,  the  product  of  the  combustion  are 
sulphurous  acid  (a  combination  of  sulphur  with  the  oxygen  of 
the  atmosphere)  and  sulphuric  acid,  (a  combination  of  the  oxy- 
gen of  the  nitre,  with  the  sulphur).  The  sulphuric  acid  thus 
generated,  combines  with  the  oxide  of  potassium  to  sulphate 
of  potash,  setting  nitrous  oxide,  or  deutoxide  of  nitrogen  free. 
But  the  heat  given  out  during  the  process  of  combustion  ex- 
pands this  gas  and  makes  it  rise  to  the  top  of  the  chambers, 
where,  by  an  aperture,  it  is  made  to  communicate  with  the 
atmosphere,  from  which  it  absorbs  another  portion  of  oxygen, 
and  is  thereby  converted  into  nitrous  acid  vapor.  These  va- 
pors being  specifically  heavier  than  air,  sink  down  upon  the 
sulphurous  acid,  and  yield  to  it  another  equivalent  of  oxygen, 
converting  it  thereby  into  sulphuric  acid  ;  which  being  rapidly 
absorbed  by  the  water,  is  immediately  obtained  in  the  liquid 
(hydrous)  state.  The  nitrous  acid  vapors  which  have  now 
lost  a  portion  of  their  oxygen,  are  again  transformed  into 
nitrous  gas,  which  does  then  reascend  to  the  roof  of  the 
chamber,  where  by  the  aperture  it  is  as  before  brought  in 
contact  with  atmospheric  air,  from  which  it  absorbs  a  fresh 
portion  of  oxygen  and  is  converted  into  nitrous  acid  vapor. 
These  sink  again  upon  the  sulphurous  acid,  and  convert 
another  portion  into  sulphuric  acid  ;  and  so  is  this  process 
continued  until  all  the  sulphurous  acid  formed,  is  converted 
into  liquid  sulphuric  acid.  Eight  parts  of  sulphur  and  one 
part  of  nitre  will  in  this  manner  produce  20  parts  of  sulphuric 
acid. 

103.      Properties  of  the  Oil  of  Vitriol,  and  of  Liquid 


Sulphuric  Jldd.  The  oil  of  vitriol,  in  its  pure  state,  is  a 
colorless,  oily  liquid,  which  destroys  rapidly  all  animal  and 
vegetable  substances,  but  may  be  mixed  with  water  in  any 
proportion.  (The  yellowish  brown  tinge  which  the  oil  of 
vitriol  of  commerce  generally  has,  is  derived  from  organic 
substances,  such  as  cork,  wood,  straw,  &c,  accidentally 
dropped  into  it).  The  Hydro-sulphuric  Acid,  when 
pure,  is  a  colorless,  oily  liquid.  It  is  inodorous,  and  dilute 
with  water  (without  water  it  is  an  active  poison)  has  a  strong 
acid  taste.  It  may  be  mixed  with  water  in  any  propor- 
tion, and  reddens  litmus  paper  even  when  largely  diluted 
with  it.  Its  specific  gravity  when  most  concentrated,  is 


SULPHUR.  147 

1.85,  that  of  water  being  1.  If  it  is  much  heavier,  it  is 
a  sign  that  it  contains  some  foreign  heavy  substances 
(commonly  sulphate  of  soda  or  lead,  from  the  manner  in 
which  it  is  manufactured  in  leaden  chambers),  and  if  it  is 
much  lighter  it  shows  that  it  has  been  diluted  with  water. 
Owing  to  its  great  affinity  for  water,  it  rapidly  destroys  all 
organic  substances  of  whose  composition  water  forms  a 
large  ingredient,  and  converts  theni  (by  absorption)  into 
charcoal.  Its  boiling  point  is  about  620  degrees  Fahren- 
heit, and  it  crystallizes  at  about  15°  below  zero. 

§  104.  Of  the  numerous  applications  of  sulphuric  acid 
to  the  arts  we  will  only  mention  a  few  highly  important 
ones.  To  those  belong  the  use  which  is  made  of  it  in  the 
manufacture  of  Glauber's  salts,  so  extensively  used  in  med- 
icine (see  Chap.  IV —  Sulphate  of  Soda)  ;  in  the  bleach- 
ing of  linen  and  cotton,  in  the  cleansing  of  rags  for  the 
manufactory  of  paper  ;  in  the  dyeing  and  printing  of  cali- 
cos, &-c.  The  annual  consumption  of  sulphuric  acid,  in 
England  alone,  amounts  to  3000  tons  ! ! 

Combination  of  Sulphur  with  Hydrogen. 

§  105.  Sulphur  combines  in  two  different  proportions 
with  hydrogen,  viz  :  In  the  proportion  of  I  equivalent  of 
sulphur  with  I  equivalent  of  hydrogen,  and  in  the  pro- 
portion of '2  equivalents  of  sulphur  with  1  equivalent  of 
hydrogen,  the  products  being  sulphuretted  hydrogen,  and 
bi-sulphuretted  hydrogen.  (The  syllable  c  6t'  signifying 
double  ;  because  sulphur  is  combined  with  a  double  pro- 
portion of  hydrogen). 

Sulphuretted    Hydrogen 

is  composed  of  1  equivalent  of  sulphur  =  16 
1          do.     of  hydrogen  =     1 

Chemical  eqvivalent  of  Sulphuretted  hydrogen  =  17. 

§  106.  Sulphuretted  hydrogen  occurs  in  nature,  combin- 
ed with  water  or  alkalies.  It  is  also  given  off  during  the 
putrefaction  of  a  variety  of  animal  substances  ;  and  may 
be  easily  obtained  for  the  sake  of  experiment,  by  subliming 


148  SULPHUR. 

sulphur  in  hydrogen  gas  (see  the  experiment  represented 
in  Fig.  CIX,  page  141).  The  two  elements,  hydrogen 
and  sulphur,  combine  during  this  process  without  a 
change  of  volume.  It  may  also  be  produced  in  abundance 
by  the  action  of  sulphuric  acid  on  sulphurct  of  iron,  a 
substance  obtained  by  melting  together  sulphur  and  iron 
filings.  Sulphuretted  hydrogen  is  by  this  means  ob- 
tained by  elective  affinity  ;  the  oxygen  contained  in  the 
water  of  the  hydro-sulphuric  acid  unites  with  the  metal 
which  remains  dissolved  in  the  acid,  setting  hydrogen  and 
sulphur  free,  which  unite  with  each  other  to  sulphuretted 
hydrogen. 

§  107.  Properties  of  Sulphuretted  Hydrogen.  Sul- 
phuretted hydrogen  is  a  colorless,  inflammable  gas,  which 
smells  and  tastes  after  foul  eggs,  and  burns  with  a  light 
blue  flame.  It  is  incapable  of  supporting  combustion  and 
totally  irrespirable  ;  when  taken  into  the  lungs  it  causes 
cramp  and  suffocation.  It  is  so  exceedingly  fatal  to  an- 
imal life  that  a  dog  dies  in  an  atmosphere  containing  only 
^thy  ;  and  a  horse  in  one,  which  contains  only  ^^  part  of 
this  gas.  When  dissolved  in  water,  it  acts  like  an  acid, 
and  reddens  litmus  paper  (see  Introduction,  page  3S).  By 
cold  and  pressure  it  may  be  reduced  to  the  liquid  state  ; 
but  it  is  immediately  transformed  again  into  gas,  when 
brought  in  contact  with  the  atmosphere. 

It  is  also  remarkable  for  its  action  upon  almost  all  me- 
tallic oxides;  when  gently  heated,  and  brought  in  contact 
with  sulphuretted  hydrogen,  they  form  sulphurous  metals 
and  water  (the  hydrogen  combining  with  the  oxygen  of 
the  oxide,  and  the  sulphur  with  the  metal).  It  is  easily 
decomposed  by  sulphuric  acid  ;  but  more  especially  by 
chlorine.  Hence  the  use  of  chloride  of  lime  in  purifying 
the  air  from  the  exhalations  of  putrefying  organic  matter. 

§  108.  Sulphur  combines  also  with  chlorine  (wherefore 
sulphuretted  hydrogen  is  decomposed  by  chlorine),  Bro- 
mine, and  Iodine.  Neither  of  these  combinations  is  of 
much  use  in  the  arts.  But  sulphur  is  not  known  to  com- 
bine with  nitrogen. 


SELENIUM.  — PHOSPHORUS.  149 


Recapitulation  of  the  principal  Binary  Combinations   of 
Sulphur. 

C  hypo-sulphurous  } 
oxygen  to  <  sulphurous  >  acid. 

Sulphur        }  (.  hypo-sulphuric 

combines  with 


C.     Selenium. 

Chemical  Equivalent  =  40. 

§  109.  This  substance  has  but  lately  (in  1817)  been 
discovered  by  Berzelius,  a  celebrated  Swedish  chemist. 
It  occurs  in  very  minute  quantities,  combined  with  some  of 
the  metals,  such  as  lead,  copper,  cobalt,  quicksilver,  silver, 
gold,  &c,  and  is  only  separated  from  them  by  an  extremely 
tedious  process.  After  fusion  it  has  a  greyish  color,  and  a 
metallic  lustre.  When  rapidly  cooling  its  color  is  reddish 
brown  —  as  a  powder  it  has  a  deep  red  color.  It  is  brittle, 
boils  at  about  12  degrees  above  the  boiling  point  of  water, 
and  when  warm  is  very  ductile. 

Selenium  combines  in  three  different  proportions  with  oxy- 
gen. The  compounds  are  oxide  of  'selenium,  selenious  acid,  and 
silenic  acid.  With  hydrogen  it  is  only  known  to  combine  in 
one  ratio,  forming  with  it  selenielted  hydrogen.  With  sulphur 
it  unites  in  all  proportions,  the  various  products  being  known 
by  the  name' of  sulphuretted  selenium. 

D.     Phosphorus. 

Chemical  Equivalent  =  1 2,    (doubtful). 

§  110.  Phosphorus  is  a  light  yellow,  soft  solid,  which 
at  the  mean  temperature  of  the  atmosphere  is  of  the  con- 
sistency of  wax,  and  exposed  to  the  atmosphere  emits 
white  luminous  vapors.  It  is  chiefly  contained  in  the 
bones  of  animals,  and  has  not  as  yet  been  found  in  its 

13* 


150  PHOSPHORUS. 

simple  form.     It  may,  however,  be  easily  procured  by  the 
following  process. 

Reduce  a  quantity  of  bones,  which  have  been  burnt  in  an 
open  fire  to  a  fine  powder  ;  and  digest  them  for  several  days 
with  half  their  weight  of  concentrated  sulphuric  acid,  adding 
enough  water  to  give  the  mixture  the  consistency  of  a  thin 
paste.  The  solution  is  then  mixed  with  twice  its  bulk  of  hot 
water,  and  after  being  well  stirred,  filtered  through  a  straining 
cloth.  (See  Fig.  IX,  page  18). 

This  solution  is  again  evaporated  to  the  consistency  of  syrup ; 
then  mixed  with  one  fourth  its  weight  of  powdered  charcoal, 
and  strongly  heated  in  an  earthen  retort.  A  large  quantity 
of  gas  will  be  formed  during  this  process,  which,  when  the 
mouth  of  the  retort  is  conducted  into  a  receiver  filled  with 
water,  will  distil  over  in  drops,  which  will  congeal  in  contact 
with  the  water.  The  solid  thus  obtained  is  pure  phosphorus. 

To  understand  this  process  it  is  necessary  to  state  that  all 
bones  are  composed  of  a  particular  salt  called  phosphate  of 
lime,  mixed,  however,  with  a  variety  of  animal  substances. 
By  burning  bones  in  an  open  fire  (which  process  is  also  called 
calcination)  the  phosphate  of  lime  is  separated  from  these  sub- 
stances, and  when  subsequently  digested  with  concentrated 
sulphuric  acid,  decomposed  into  its  constituent  principles, 
phosphoric  acid  and  lime.  The  lime  unites  by  elective  affini- 
ty with  the  sulphuric  acid  to  an  insoluble  compound  (sulphate 
of  lime)  and  the  phosphoric  acid  remains  dissolved  in  the  solu- 
tion ;  consequently,  when  the  solution  is  filtered,  nothing  but 
pure  sulphuric  acid  will  pass  through  the  straining  cloth. 
When  the  solution  is  afterwards  evaporated  and  distilled  with 
charcoal  at  a  strong  heat,  the  charcoal  unites  with  the  oxygen  of 
the  acid  and  sets  the  phosphorus  free.  This  passes  in  form  of 
gas  from  the  retort  into  the  receiver,  and  congeals  in  contact 
with  the  water. 

§  111.  Properties  of  Phosphorus.  Pure  phosphorus, 
obtained  in  the  manner  we  have  just  described,  is  a  soft, 
yelolw  solid,  which  by  exposition  to  solar  light,  espe- 
cially to  the  violet  rays  of  the  spectrum,  changes  into 
red,  but  rnay  be  rendered  perfectly  colorless  by  a  second 
distillation.  It  is  so  exceedingly  inflammable  that  it  may 
be  ignited  by  mere  friction,  or  by  the  natural  heat  of  the 
palm  of  the  hand.  Owing  to  its  great  affinity  for  oxygen 
it  combines  with  it  at  the  common  temperature  of  the  at- 


PHOSPHORUS.  151 

mosphere,  so  that  in  order  to  preserve  it,  it  is  necessary  to 
keep  it  under  water.  In  contact  with  air  it  emits  a  light 
smoke  (owing  to  its  slow  combustion  with  oxygen)  and 
a  smell  somewhat  like  garlic;  but  in  the  dark  it  throws 
out  a  beautiful  greenish  light.  Its  specific  gravity  is  1.7, 
that  of  water  being  1.  It  is  perfectly  tasteless,  but  when 
taken  into  the  stomach  proves  a  very  active  poison. 

It  is  insoluble  in  water,  but  readily  combines  with  oil 
or  ether,  to  which  substances  it  communicates  the  proper- 
ty of  throwing  out  light  in  the  dark. 

Its  affinity  for  oxygen  is  so  great  that  it  will  take  up  of 
this  gas  more  than  1J  times  its  own  weight,  and  so  easily 
does  it  ignite  by  friction  that  it  is  used  in  the  construction 
of  phosphoric  match  boxes. 

Combinations  of  Phosphorus  with  Oxygen. 

§  112.  Phosphorus  combines  with  oxygen  in  five  dif- 
ferent proportions,  forming  with  it  two  oxides  and  three 
acids,  viz  :  White  oxide  of  Phosphorus,  Red  oxide 
of  Phosphorus,  hypo-phosphorus  acid,  Phosphorous  aczW, 
and  Phosphoric  acid.  The  exact  proportions  in  which 
phosphorus  combines  with  oxygen  being  not  known,  and 
these  compounds  being  of  little  application  to  the  arts,  we 
will  only  describe  the  most  remarkable  of  them, 

Phosphoric  Acid, 

which  is  composed  of  1  equivalent  of  Phosphorus  =  12 
and  2  equivalents  of  Oxygen  (each  =  8)  =  16 


Consequently,  chemical  equiv.  of  Phosphoric  acid  =  28. 

§  113.  This  compound  of  phosphorus  occurs  in  na- 
ture, combined  with  lime,  clay,  oxide  of  iron,  lead,  cop- 
per and  manganese,  &,c  ;  but  it  may  be  obtained  by  art,  by 


152 


PHOSPHORUS. 


Fig.  CX. 


burning  phosphorus  in  atmospher- 
ic air,  or  better  in  pure  oxygen 
gas,  (see  the  adjoining  figure). 
(The  phosphorus  may  be  ignited 
by  a  red-hot  wire,  and  must  be  in- 
troduced into  the  jar  from  under 
the  water,  to  prevent  spontaneous 
combustion  by  friction  or  the  heat 
of  the  hand).  During  combustion 
dense  white  vapors  will  be  form- 
ed, which,  like  snow,  fall  to  the 
bottom  of  the  jar,  and  consti- 
tute what  is  called  the  pure,  an- 
hydrous, phosphoric  acid.  This 
unites  afterwards  with  the  water  to  hydro-phosphoric  acid, 
and  may  be  evaporated  to  dryness.  It  may  also  be  obtain- 
ed from  the  action  of  phosphorus  or  nitric  acid,  or  by  di- 
gesting calcined  bones  with  sulphuric  acid,  as  we  have 
seen  in  the  process  of  procuring  phosphorus.  (§107.) 

§  114.  Properties.  Phosphoric  acid  is  a  colorless, 
inodorous,  transparent  liquid,  which  easily  absorbs  water 
from  the  atmosphere,  and  has  all  the  essential  qualities  of 
a  powerful  acid  (Introduction,  page  38).  It  has,  however, 
thus  far,  no  technical  application. 

Combinations  of  Phosphorus  with  Hydrogen. 

§  115.  Phosphorus  combines  with  hydrogen  in  two 
different  proportions  ;  the  products  are  Proto-phosphuret- 
ted  hydrogen,  and  Per-phosphuretted  hydrogen. 

Proto-phosphur cited  Hydrogen 

is  composed  of  1  equivalent  of  Phosphorus  =  12 
and  2  equivalents  of  Hydrogen  (each  1)  =   2 


Consequently,  chemical  equiv.  of  Proto-phosphu- 

retted  hydrogen  =  14. 


PHOSPHORUS. 


153 


Per-phosphuretted  Hydrogen, 

on    the  contrary,  is   composed  of  1  equivalent  of 

phosphorus  =  12 

1  equivalent  of  Hydrogen  =    1 

Chemical  equiv.  of  per-phosphuretted  hydrogen  =  13. 

Both  compounds  consist  of  phosphorus  dissolved  in  hy- 
drogen. 

§  116.     Per-phosphuretted  hydrogen    is    obtained,  by 
boiling  Phosphorus  in  a  small  retort  with  a  hot  solution  of 
potash,  which  must  entirely  fill  the  vessel.     The  gas  thus 
Fig.  CXI. 


generated  must  be  collected  by  the  pneumatic  tub,  employ- 
ing a  hot  solution  of  potash  instead  of  water.  During  the 
boiling  of  the  liquid,  the  oxygen  of  the  water  unites  with 
part  of  the  phosphorus  to  phosphorus  acid,  which  combin- 
ing with  the  potash,  sets  the  hydrogen  of  the  water  free. 
This,  under  the  influence  of  heat,  combines  with  the  re- 
maining portion  of  phosphorus  to  phosphuretted  hydrogen. 
When  the  gas,  as  it  is  extricated,  is  allowed  to  escape 
from  under  the  surface  of  the  alkaline  solution  into  the  air, 
each  bubble  as  it  rises  will  spontaneously  take  fire  and  ex- 
plode, leaving  after  the  explosion  an  horizontal  ring  (see  the 
figure)  of  white  smoke,  which  preserves  its  form  for  a  consid- 
erable time,  and  becomes  larger  as  it  ascends. 

§   117.       Properties    of    per-phosphuretted    hydrogen. 
Per-phosphuretted  hydrogen  is  a  colorless  gas  of  a  highly 


154  PHOSPHORUS. 

offensive  smell  (resembling  garlic,  or  foul  fish),  which  in 
contact  with  atmospheric  air,  or  pure  oxygen,  becomes 
spontaneously  inflamed,  and  explodes,  as  we  have  seen 
from  the  last  experiment  (Fig.  CXI).  It  is  more  than  13 
times  heavier  than  hydrogen  gas,  and  but  slightly  soluble 
in  water.  When  suffered  to  stand  for  some  time  in  a 
glass  receiver,  it  becomes  spontaneously  decomposed,  and 
deposits  phosphorus.  A  series  of  electric  sparks  pass 
through  it,  produces  a  similar  effect,  and  precipitates  phos- 
phorus. 

Proto-phosphuretted  hydrogen  is  produced  by  heating  phos- 

fhorus  acid  in  close  vessels,  secluded  from  contact  with  air. 
t  is  a  colorless  gas,  resembling  per-sulphuretted  hydrogen 
in  nearly  all  essential  properties.  It  does  not,  however,  in- 
flame spontaneously  when  brought  in  contact  with  atmospheric 
air  ;  but  when  mixed  with  it,  or  pure  oxygen,  it  detonates  vio- 
lently on  the  application  of  an  electric  spark. 

Jl  beautiful  Experiment  may  be  made  by  mixing  10  parts 
of  water  with  1  part  of  phosphorus,  2  parts  of  granulated 
zinc,  and  6  parts  of  concentrated  sulphuric  acid.  Owing  to 
the  decomposition  of  the  water,  and  a  subsequent  combination 
of  its  hydrogen  with  the  phosphorus,  per-phosphuretted  hydro- 
gen, will  be  generated  and  rise  in  little  bubbles.  These,  in 
contact  with  atmospheric  air,  become  spontaneously  inflamed, 
and  burn  with  a  bright  flame  like  phosphorus. 

Other  Combinations  of  Phosphorus. 

§  118.  Phosphorus  combines  also  with  carbon,  sul- 
phur, selenium,  chlorine,  iodine,  boron,  and  the  metals. 
These  combinations  have  thus  far  been  little  examined, 
and  are  of  little  or  no  application  in  the  arts. 

Recapitulation  of  the  most  important  Binary  Combinations 
of  Phosphorus. 

(  white  oxide  \    c    r       7 
(red  oxide      \°tp>»>P>>»""- 
«W«»to     hypo-phosphorous 


»»*•*«.  to  ***** 


BORON.  155 


E.     Boron. 

Chemical  Equivalent  =  6,  (doubtful). 

§  119.  This  element  is  not  found  in  its  simple  state  ; 
but  is  extracted  from  boracic  acid,  a  substance  we  are 
about  to  describe  in  the  next  section. 

For  this  purpose  potassium  (a  metal)  may  be  heated  with 
boracic  acid,  in  a  copper  tube  to  about  302°  Fahrenheit. 
When  hey  become  red-hot,  the  oxygen  of  the  acid  combines 
with  the  metal,  and  sets  the  boron,  which  is  the  basis  of  boracic 
acid,  free. 

Properties.  It  appears  as  a  dark  green  powder,  which 
is  inodorous,  tasteless,  and  but  sparingly  soluble  in  water. 
Heated  in  close  vessels  it  undergoes  no  change,  but  when 
heated  in  the  open  air  to  about  600°  Fahrenheit,  it  burns 
with  a  pale  green  flame,  the  product  being  boracic  acid. 

Boracic  Acid 

is  probably  composed  of  1   equivalent  of  boron  =    6 
and  2  equivalents  of  oxygen  (each  =  8)  =  16 


Whence,  chemical  equivalent  of  boracic  acid  =  22. 

^  120.  This  is  the  only  combination  of  boron  with 
oxygen.  It  is  a  substance  which  is  generally  obtained  in 
form  of  crystals,  and  is  found  mixed  with  a  little  sulphur 
on  the  walls  of  cellars  and  caves,  and  at  the  craters  of  vol- 
canos.  It  is  also  contained  in  some  of  the  springs.  It 
may  be  obtained  by  art,  by  dissolving  borax  (a  substance 
resembling  alum,  and  which  is  imported  from  India  under 
the  name  of  Tincal),  in  boiling  water,  adding  to  it  half  its 
weight  of  dilute  sulphuric  acid.  When  the  solution  is 
evaporated  and  cooled,  boracic  acid  is  precipitated  in  form 
of  scaly,  shining  crystals. 

Borax  is  a  combination  of  boracic  acid  with  soda.  When  it 
is  dissolved  in  hot  water,  and  sulphuric  acid  is  added,  the  soda 
combines  by  elective  affinity  with  the  sulphuric  acid,  and  the 
boracic  acid  sinks  to  the  bottom. 

§   121.    Properties.     It  is  inodorous,  possesses  but  very 


156  IODINE. 

little  taste,  and  is  sparingly  soluble  in  water,  with  which  it 
forms  a  solution  which  reddens  litmus  paper.  It  is  also 
dissolved  by  alcohol,  to  whose  flame  it  gives  a  beautiful 
green  color.  Boracic  acid  is  used  in  the  manufac- 
tory of  artificial  borax,  which  is  much  employed  in  medi- 
cine. It  is  also  used  in  calico  printing,  especially  in 
France,  and  in  coloring  gold. 

Boron  combines  yet  with  sulphur,  chlorine,  fluorine, 
and  the  Metals. 

F.     Iodine* 

Chemical  Equivalent  =  124. 

§  122.  This  element  does  not  occur  in  its  simple  form 
in  nature  ;  but  is  often  found  combined  with  some  of  the 
metals,  particularly  with  sodium,  a  substance  of  which 
we  shall  speak  in  the  next  chapter.  It  has  lately  been  dis- 
covered also  in  the  Mexican  silver  mines,  and  in  many  of 
the  lead  ores  of  South  America.  It  is  commonly  extract- 
ed from  the  ashes  of  sea-weeds,  or  from  a  substance  call- 
ed kelp,  generated  during  the  manufacture  of  soda. 

The  process  is  simply  this  :  The  ashes  of  sea-weeds,  or 
kelp,  are  dissolved  in  water,  which  upon  evaporation,  leaves  a 
salt  called  carbonate  of  soda,  in  form  of  crystals.  These  be- 
ing removed,  the  remaining  liquid  is  put  into  a  tubulated  retort, 
(see  Fig.  CVII,  page  136),  and  sulphuric  acid  is  poured  upon 
it.  As  soon  as  this  is  done  beautiful  violet  vapors  appear, 
which  become  condensed  in  the  receiver  in  crystalline  plates, 
resembling  plumbago  (see  page  123),  and  may  afterwards  be 
dried  between  folds  of  blotting  paper.  A  small  quantity  of 
oxide  of  manganese,  added  to  the  liquid  in  the  retort,  facili- 
tates the  process. 

§  123.  Properties  of  Iodine.  Iodine  is  a  substance 
which  at  the  common  temperature  of  the  atmosphere  is 
of  a  greyish-black  color,  and  possesses  a  metallic  lustre. 
Its  other  .properties  resemble  chlorine  (see  §  65,  page 
103),  and  it  is  a  strong  poison  when  used  in  large  quan- 

*  From  a  Greek  word  signifying  violet  colored,  because  its  vapors 
have  a  beautiful  violet  color. 


IODINE.  157 

titles.  In  small  quantities  it  is  used  for  medicinal  purposes. 
Its  taste  is  sharp  and  acrid,  and  continues  for  a  long  time 
upon  the  tongue.  It  destroys  vegetable  colors  and  gives 
the  skin  a  yellow  stain,  which  however,  soon  disappears. 
It  fuses  at  about  225  degrees,  and  becomes  converted  into 
beautiful  purple  vapors  when  heated  to  350  degrees  Fah- 
renheit. It  is  (like  chlorine)  a  non-conductor  of  electri- 
city, and  but  sparingly  soluble  in  water  ;  but  is  easily  dis- 
solved by  ether,  alcohol,  or  oil  of  turpentine.  With 
starch  it  forms  a  compound  of  a  beautiful  indigo  color, 
which  affords  a  means  of  detecting  its  presence  even  in 
very  minute  quantities. 

It  is  principally  used  in  medicine,  and  in  the  manufac- 
tory of  Iodide  of  quicksilver,  which  is  a  red  pigment,  em- 
ployed in  cotton-printing  and  painting. 

Combination  of  Iodine  with  Oxygen  —  lodic  Acid. 

Chemical  composition  :     1  equivalent  of  Iodine  =  124 
5  equivalents  of  Oxygen  (each  =  8)  =    40 


Consequently,  chemical  equivalent  of  lodic  acid  =  164. 

§  124.  Iodine  combines  in  only  one  proportion  with 
oxygen.  The  product  is  iodic  acid,  a  white,  half-transpa- 
rent solid,  which  is  perfectly  inodorous,  and  has  a  sharp, 
sour,  astringent  taste.  It  is  obta-ined  by  bringing  protoxide 
of  chlorine  (see  §  66,  page  144)  in  contact  with  iodine, 
and  applying  a  gentle  heat  to  the  orange- colored  vapors 
which  are  thus  formed.  By  this  means  vapors  of  iodine 
and  chlorine  are  given  off,  and  a  compound  of  iodine  and 
oxygen  remains.  No  particular  application  is  made  of  this 
compound  in  the  arts. 

Combination  of  Iodine  with  Hydrogen  —  Hydriodic  Acid. 

Chemical  composition  :     1  equivalent  of  Iodine  =124 
1        do.     of  Hydrogen  =      1 

Consequently,  chemical  equiv.  of  Hydriodic  acid  =  125. *~ 

§  125.  Iodine  combines  with  hydrogen  to  hydriodic 
acid.  This  combination  is  effected  by  the  action  of 

14 


158  BROMINE. 

moistened  iodine  on  phosphorus.  It  is  effected  by 
double  elective  affinity  (see  Intro,  page  9).  The  oxygen 
of  the  water  combines  with  the  phosphorus,  and  the  hy- 
drogen with  the  iodine. 

Properties.  It  is  a  colorless  gas,  of  a  very  pungent 
and  an  intensely  sour  taste  ;  which  reddens  blue  veg- 
etable colors  without  bleaching  them.  Combined  with 
those  substances  called  bases  (see  Intro,  page  38)  it  forms 
salts,  of  which  some  are  now  used  in  medicine. 

§  126.  Iodine  combines  yet  with  carbon,  and  in  seve- 
ral proportions  with  sulphur  and  phosphorus.  It  has  like- 
wise a  strong  affinity  for  boron,  nitrogen,  silicon,  and  the 
metals. 

Recapitulation  of  the  Principal  Binary   Combinations  of 
Iodine. 

C  oxygen  to  iodic  acid. 
Iodine  combines  with  < 

(  hydrogen  to  hydriodic  acid. 

G.     Bromine* 

Chemical  Equivalent  =  75. 

§  127.  This  is  an  element  but  recently  discovered  (in 
1826)  by  Balard,  a  French  chemist.  It  may,  like  iodine, 
(to  which  it  bears  a  strong  analogy),  be  obtained  from  the 
ashes  of  sea-weeds,  or  also  from  sea-water. 

The  washings  of  sea- weeds,  or  the  liquor  which  remains  in 
salt-pans  after  sea  water  has  been  evaporated  for  the  purpose 
of  obtaining  common  table  salt,  is  mixed  with  a  solution  of 
chlorine.  This  mixture  being  distilled  by  the  application  of  a 
gentle  heat,  the  vapors  must  be  made  to  pass  over  chloride  of 
lime.  This  salt,  after  absorbing  the  watery  parts,  will  leave  a 
few  drops  of  a  blackish-red,  volatile  liquid,  which  is  then  the 
pure  bromine. 

^  128.  Properties  of  Bromine.  At  the  common  tem- 
perature of  the  atmosphere  it  is  a  dark  red  fluid  ;  thin 

*  From  a  Greek  word,  signifying  *  a  strong,  disagreeable  smell.' 


SILICON.  159 

strata  of  it  viewed  through  the  light  appear  of  a  beautiful 
hyacinth  color.  Its  smell  is  exceedingly  disagreeable, 
and  its  taste  sharp  and  nauseous.  At  a  few  degrees  below 
zero  of  Fahrenheit's  thermometer,  it  congeals,  and  becomes 
a  grey,  crystalline  mass.  It  does  not  corrode  the  skin 
permanently,  is  exceedingly  volatile,  boils  at  a  tempera- 
ture of  116°  Fahrenheit,  and  gives  off  red  vapors.  It  is 
sparingly  soluble  in  water  ;  but  is  readily  dissolved  in 
ether,  alcohol,  and  many  of  the  fat  oils. 

Combinations  of  Bromine. 

§  129.  Bromine  combines  with  oxygen  to  bromic  acid, 
a  colorless,  inodorous,  sour  liquid,  which  reddens  litmus 
paper  ;  and  is  composed  of 

1  equivalent  of  bromine  =   75 
and  5  equivalents  of  oxygen  (each  =  8)  =    40 

Consequently,  chemical  equiv.  of  bromic  acid  =  115. 

With  hydrogen  it  combines  in  2  proportions,  forming 
hydrobromous  and  hydrobromic  acid.  The  latter  (the 
most  remarkable  of  the  two),  is  a  colorless  gas,  which 
tastes  and  smells  sour,  is  rapidly  absorbed  by  water,  and 
emits  white  vapors.  A  solution  of  it  in  water  has  nearly 
the  same  properties. 

Bromine  unites  yet  with  chlorine,  carbon,  sulphur  and 
phosphorus.  Through  the  intermission  of  hydrobromic 
acid  it  unites  with  the  metals  potassium,  tin,  zinc,  and 
iron. 

Recapitulation  of  the  Principal  Binary  Combinations  of 
Bromine. 

oxygen  to  bromic  acid. 
to 


H.     Silicon  (Silicium). 

Chemical    Equivalent  =  8. 

§  130.     This   substance,  (discovered  by  Berzelius  in 
1823)  was  formerly  known  only  in  combination  with  the 


160  SILICON. 

fixed  alkalies,  potash,  soda,  lithia,  lime,  &c.  (see  Chap. 
III).  From  these  combinations,  silicon,  or  silicium  itself 
is  obtained  by  the  action  of  heated  potash.  It  is  a  dark 
brown  powder,  without  metallic  lustre,  which  adheres  easily 
to  other  substances,  and  is  a  non-conductor  of  electricity. 
It  may  be  exposed  to  the  most  powerful  heat  without 
fusing,  and  with  the  exception  of  fluor  (of  which  we 
shall  soon  speak),  is  not  acted  upon  by  any  of  the  mineral 
acids. 

Combination  of  Silicon  with  Oxygen  —  Silex. 

Chemical  composition  :     1  equivalent  of  Silicon  =    8 
1         do.      of  Oxygen  =    8 

Consequently,  chemical  equivalent  of  Silicon  =  16. 

§  131.  Silicon  combines  with  oxygen  only  in  one  pro- 
portion. The  product  of  this  combination,  which  is  an 
oxide  of  silicon,  is  called  silex,  silica,  or  silicioiis  earth, 
is  the  principal  ingredient  of  all  fossils  in  the  mineral 
kingdom.  It  is  found  almost  in  its  simple  form  in  rock- 
crystal,  flint  and  agate.  In  many  other  fossils  it  is  found 
combined  with  clay,  lime,  magnesia,  &c.  It  has  also 
been  discovered  in  plants,  and  animal  matter,  viz.  :  in  the 
enamel  of  the  teeth,  in  bones,  &c. 

Silex  is  obtained  by  art  in  the  following  manner :  One  part 
powdered  quartz  is  melted  in  a  crucible  with  three  or  four 
parts  of  pure  carbonate  of  potash  (a  salt  hereafter  to  be  de- 
scribed) and  when  cooled,  dissolved  in  dilute  muriatic  acid. 
The  precipitate  which  will  be  thus  formed  must  be  thoroughly 
washed  and  dried  until  it  is  perfectly  tasteless. 

§  132.  Properties  of  Silex.  Silex  obtained  in  the 
manner  just  described,  is  a  white,  inodorous,  tasteless  pow- 
der, which  feels  harsh  when  rubbed  between  the  fingers, 
and  melts  only  in  the  highest  degree  of  heat  produced  by 
the  most  powerful  galvanic  batteries.  It  is  perfectly  in- 
soluble in  water,  and,  with  the  exception  of  fluoric  acid, 
in  all  the  mineral  acids.  Combined  with  hydrogen  it 
forms  a  hydrate,  which  in  nature  occurs  as  a  precious 
stone,  known  by  the  name  of  opal.  Silex  is  of  inestima- 


SILICON.  161 

ble  application  in  the  manufactory  of  glass,  earthen  ware 
and  porcelain. 

Silicious  earth  (silica)  occurs  as  principal  ingredient  in  the 
following  fossils  : 

1.  In  Rock,  or  Mountain  Crystal.  —  Properties.     It  is  color- 
less, sometimes  yellow,  brown  or  black  (as  topaz) ;  has  a  strong 
glassy  lustre,  is  perfectly  transparent,  and  gives  sparks  on 
steel.     It  abounds  particularly  in  Madagascar,  and  the  island 
of  Ceylon. 

2.  In  Jlmathyst.  —  Properties.     It  has  a  violet  color,  glassy 
lustre,  and  is  transparent.     The  finest  amathysts  are  found  in 
Siberia,  at  the  foot  of  the  Ural  mountains,  and  in  Brazil. 

3.  In  Common  Quartz.  —  Its  color  is  a  mixed  white  (milk- 
quartz),  gray,  red   (rose-quartz),  brown  (iron  or  flint  quartz), 
or  blue  (sapphire  quartz).     It  forms  a  principal  part  of  most  all 
mountainous  masses,  particularly  of  granite.     It  is  used  most 
extensively  in  the  manufactory  of  glass,  porcelain  and  china- 
ware.     It  is  also  a  common  building  material,  and  is   used  in 
the  paving  of  streets  and  roads.     (In  France  it  is  also  employ- 
ed for  mill-stones). 

4.  In  Flint.  —  This  is  generally  found  in  round  masses,  of  a 
grey,  yellow,  brown,  or  dark  color,  in  layers  of  chalk  or  lime- 
stone.    It  is  used  in  the  manufactory  of  English  china  (jlint- 
ware),  and  glass  (flint-glass).     To  the  same  species  of  stone 
belong  also  Agate,  Chalcedon,  Jaspis,  Carnelion,  and    Chryso- 
prase. 

5.  In  Pumice,  a  spungy,  glassy  stone,  with  a  lustre  like 
mother  of  pearl,  and  a  yellowish,  sometimes  green,  color.     It 
is  a  volcanic  product,  forming  great  masses  in  the  neighbor- 
hood   of  volcanos,  particularly  in    Italy,  Iceland,    Quito,  and 
Mexico.     It  is  used  for  polishing  ivory, marble,  alabaster,  parch- 
ment, and  leather. 

6.  In  Sand.  —  This   is   a  product  of  the  decomposition  of 
various  kinds  of  stones  and  rocks,  especially  of  stones  which 
abound  in  quartz,  glimmer,  and  granite.     It  is  found  in  all  low 
countries,  in  the  beds  of  rivers,  and  on  the  sea-shore.     It  is  of 
almost  universal  application   in  the  arts  ;  and  is  used  in  the 
manufactory   of  glass,  in  the  preparation  of  mortar,    in  the 
grinding,  polishing,  and  cleansing  of  articles  ;  in  the  manufac- 
tory of  bricks,  in  the  casting  of  metals,  &c. 

Silicious  earth  is  also  contained  in  tripoli  or  rotten  stone,  a 
yellowish  white  earthy  substance,  which  is  found  in  many 


162  FLUORINE. 

countries,  especially  in  the  neighborhood  of  coal  mines.     It  is 
used  for  polishing  metals,  particularly  brass. 

Recapitulation. 
Silicon  combines  with  oxygen  to  Silex,  or  Siliceous  earth. 

I.     Fluorine   (1) 

Chemical  Equivalent  (not  ascertained). 

§  133.  Fluorine  is  a  substance  whose  existence  is  not 
yet  satisfactorily  proved.  It  was  first  (by  Thenard,  a 
French  chemist)  supposed  to  exist  in  all  three  kingdoms 
of  nature,  combined  with  the  metals  calcium,  alumium, 
sodium,  and  yttrium  (see  Chap.  III).  It  is  believed  to  be 
analogous  to  bromine,  iodine,  and  chlorine,  and  to  form 
with  hydrogen  fluoric  acid,  like  chloric  acid,  iodic  acid, 
bromic  acid,  which  are  products  of  chlorine,  iodine,  and 
bromine  combined  with  hydrogen. 

Fluoric   Acid. 
Chemical   Equivalent  =10. 

§  134.  Fluoric  Jlcid  (hydro-fluoric  acid),  is  obtained 
by  the  action  of  strong  sulphuric  acid  on  the  well-known 
substance  fluor-spar.  For  this  purpose  the  retort  and  re- 
ceiver must  be  made  of  platinum  or  lead,  glass  vessels 
being  instantly  corroded  and  destroyed  by  this  acid, 
which  easily  combines  with  silicon,  the  principal  ingredi- 
ent of  glass. 

Fluor-spar  is  found  crystallized  in  various  colors,  green,  red, 
yellow,  &c.  It  assists  the  fusion  of  earthy  minerals  in  metal- 
lurgical operation.  If  fluorine  is  a  substance  analogous  to 
chlorine,  iodine,  and  bromine,  then  fluor-spar  may  be  sup- 
posed to  be  a  fluoride  of  calcium. 

§  135.  Properties  of  Fluoric  acid.  It  is  a  colorless 
liquid  of  an  exceedingly  sharp,  sour  taste,  a  pungent, 
penetrating  smell,  and  a  strong  caustive  power,  which 
when  exposed  to  the  atmosphere,  emits  white  fumes.  It 


FLUORINE.  1(33 

absorbs  water  largely,  is  exceedingly  volatile,  boils  at  about 
60°  Fahrenheit,  and  does  not  congeal  at  40  degrees  below 
zero  of  the  same  thermometer.  Its  vapors  are  very  ob- 
noxious to  animals  and  all  organic  formations,  which  are 
speedily  destroyed  by  them.  (This  is  the  reason  why  the 
investigation  of  its  properties,  and  probably  also  its  de- 
composition into  fluorine  and  hydrogen  is  so  difficult,  and 
indeed,  almost  impracticable.)  It  may  be  mixed  with  wa- 
ter in  any  proportion,  the  mixture  giving  off  great  heat. 
If  lime  is  thrown  into  it,  heat  and  water  are  given  off,  and 
a  substance  similar  to  fluor-spar  (probably  fluoride  of  cal- 
cium) is  produced. 

Owing  to  its  affinity  for  silicon  (the  principal  ingredient 
of  glass)  it  has  the  peculiar  power  of  operating  on  glass. 
Plates  of  glass,  covered  with  a  composition  of  bees-wax 
and  oil  of  turpentine  may  be  etched  with  it  (or  its  vapors) 
like  a  copper-plate. 

Other  Combinations  of  Fluorine. 

§  136.  There  are  but  two  more  combinations  of  flu- 
orine with  other  substances  known  —  viz.  :  with  boron, 
the  product  of  which  is  fluoboric  acid;  and  with  silicon, 
the  product  of  which  is  fluoride  of  silicon.  The  former 
is  a  colorless  gas,  of  a  pungent,  suffocating  smell,  and  a 
strong,  sour  taste.  It  absorbs  water,  and  produces  white 
fumes  in  contact  with  the  atmosphere.  The  properties  of 
the  latter  are  similar  to  those  we  have  just  mentioned. 

Recapitulation,  of  the  most  important  Binary   Combina- 
tions of  Fluorine. 

C  Hydrogen  to  fluoric  acid. 
Fluorine  combines  with  2  Boron  to  fluoboric  acid, 

(J  Silicon  to  fluoride  of  silicon. 


164  RECAPITULATION 


EEC  A  PIT  U  LATION. 

Questions  for  reviewing    the  most    important  Principles 
contained  in    Chapter  II. 

A.     QUESTIONS  ON  CARBON. 

[§  72.]  What  other  non-metallic  elements  are  there, 
besides  the  four  gases,  oxygen,  hydrogen,  nitrogen,  and 
chlorine  ?  What  characterizing  properties  have  these  in 
common  with  the  gases. 

73.]    .What  is  the  chemical  equivalent  of  carbon, 
f  what   substance  does  carbon  form  the   principal  in- 
gredient 1 

Where  are  diamonds  principally  found  ?  What  is  the  spe- 
cific gravity  of  diamond.  What  becomes  of  diamonds  .when 
submitted  to  the  heat  produced  in  the  focus  of  a  burning-glass, 
or  when  burnt  in  pure  oxygen  ?  What  are  the  products  of 
the  combustion  of  diamond  ? 

Describe  the  principal  properties  of  plumbago.  For  what 
is  it  used  ? 

What  are  the  principal  properties  of  Anthracite  coal  ? 
Where  is  it  chiefly  found  ? 

What  are  the  properties  of  Lehigh  coal  ? 

What  are  the  properties  of  black  and  brown  coal  ? 

What  does  turf  consist  of? 

How  is  vegetable  charcoal  obtained  ?  For  what  purpose  is 
charcoal  used  ?  What  is  its  most  remarkable  property  ?  Is 
charcoal  affected  by  heat,  when  submitted  to  its  action  in  close 
vessels  ?  What  influence  does  charcoal  exercise  on  other 
bodies  ?  What  does  its  mechanical  structure  enable  it  to  do  ? 
How  is  animal  charcoal  obtained  ? 

Why  has  charcoal  so  different  an  appearance  from  diamond, 
both  substances  being  composed  of  the  same  element  ?  What 
is  the  probable  reason  that  diamond  has  not  as  yet  been  gen- 
erated, or,  in  other  words,  why  has  not  carbon  been  obtained 
in  its  pure,  crystallized  state  ? 

[§  74.]  In  how  many  different  proportions  does  carbon 
combine  with  oxygen  ?  What  two  products  of  these  com- 
binations deserve  our  special  notice  ? 

What  is  the  chemical  composition  of  carbonic  oxide  ? 


OP    CHAPTER    II.  165 

[§  75.]     Does  carbonic  acid  occur  in  nature?     How 
then  is  it  procured  by  art  ? 

How  do  you  explain  both  processes  ? 

76.]     What  are  the  principal  properties  of  carbonic 


oxe 

[§  77.]  What  is  the  chemical  composition  of  carbonic 
acid  1  Where  is  carbonic  acid  found  ?  By  what  other 
processes  is  it  continually  produced  ? 

By  what  process  may  it  be  obtained  by  art  1  (Explain 
the  experiment  represented  in  Fig.  CII). 

Explain  this  process. 

[§  78.]  What  are  the  principal  properties  of  carbonic 
acid? 

Why  is  there  danger  from  burning  charcoal  in  a  confined 
room  ? 

[§  79.]  What  is  the  cause  of  the  agreeable  pungent 
taste,  common  to  all  sparkling,  fermenting  liquors  ? 
What  is  the  pleasant,  fresh  taste  of  pump-water  owing  to  ? 
What  then  constitutes  the  principal  difference  between 
river  and  pump  water  ? 

What  apparatus  was  formerly  used  for  impregnating  water 
or  any  other  liquid,  with  carbonic  acid  ?  (Describe  Fig.  CIIIj. 

[§  80.]  Why  must  pure  water  not  become  turbid  when 
mixed  with  lime  water  ? 

[§  81.]  In  how  many  different  proportions  does  car- 
bon combine  with  hydrogen  ?  What  are  the  products  ? 

[§  82.]  What  is  the  chemical  composition  of  sub-car- 
buretted  hydrogen  ? 

Where  is  this  gas  found  ?  Where  else  is  it  to  be  found? 
By  what  means  may  it  be  procured  for  examination  ? 

[§  83.]  What  are  the  characterizing  properties  of  sub- 
carburetted  hydrogen  ? 


What  has  been  observed  respecting  the  temperature  which 
is  necessary  to  ignite  an  inflammable  mixture  of  gases  ? 
What  discovery  did  Dr  Wollaston  make  ?  To  what  idea  was 


166  RECAPITULATION 

Sir  Humphrey  Davy  led  by  this  discovery?  How  was  this 
idea  realized  ? 

Describe  Davy's  safety  lamp  (Fig.  CV). 

Explain  its  operation. 

By  what  experiment  can  you  show  that  wire-gauze  complete- 
ly intercepts  the  flame  of  any  burning  substance  ?  What  does 
this  serve  to  explain  ? 

[§  84.]  What  is  the  chemical  composition  of  carbu- 
retted  hydrogen  ?  Is  this  compound  found  in  nature,  or 
is  it  merely  a  product  of  art  ?  How  is  it  obtained  ? 

Explain  this  process  ? 

[§  85.]  What  are  the  properties  of  carburetted  hydro- 
gen ? 

[§  86.]  What  application  is  made  of  carburetted  hy- 
drogen, or  olefiant  gas  ? 

On  what  does  the  brilliancy  of  other  gases  depend  ?  How 
does  diamond  burn  in  pure  oxygen  gas  ? 

By  whom  was  gas  light  first  employed  for  illumination? 
Who  introduced  it  first  into  England  1  From  what  was  the 
gas  used  in  Europe  first  prepared  ?  How  is  the  olefiant 
gas  used  in  America  prepared  ?  By  what  process  is  the 
oil  decomposed  and  yields  the  gas  ?  Is  the  gas  procured 
from  resin  cheaper  or  dearer  than  that  prepared  from  oil  ? 

Why  has  carburetted  hydrogen  been  called  olefiant  gas  ? 

Are  there  any  other  combinations  between  hydrogen  and 
carbon,  besides  those  you  have  mentioned  ? 

[§  87.]  What  is  the  chemical  composition  of  cyano- 
gen ?  Does  this  gas  occur  in  nature?  By  what  means 
then  may  it  be  obtained  ? 

[§  88.]  What  are  the  principal  properties  of  cyano- 
gen ?  What  is  its  most  remarkable  property  ? 

[§  89.]  In  how  many  different  proportions  does  cyan- 
ogen combine  with  oxygen  ?  What  are  the  products  ? 

[§  90.]  What  is  the  chemical  composition  of  Prussic 
acid  ?  In  what  substances  is  this  acid  principally  con- 
tained ?  By  what  process  may  it  be  obtained  ? 

How  is  this  process  explained  ? 


OP    CHAPTER    II.  167 

[  §  91.]  What  are  the  properties  of  Prussic,  or  hydro- 
cyanic acid  ? 

Can  this  acid  be  -very  well  preserved  for  any  length  of 
time  ?  Why  not  1  By  what  is  its  first  stage  of  decompo- 
sition marked  ?  What  properties  does  it  then  lose  ? 

[^  92.]  In  what  respect  does  Prussic  acid  differ  from 
other  acids  you  have  thus  far  become  acquainted  with  ? 

What  does  it  form  in  combination  with  those  substances 
called  bases  ?  To  what  pole  does  it  adhere,  when  it  is 
separated  again  from  these  substances  by  the  agency  of 
galvanic  electricity  ? 

By  what  experiment  is  it  proved  that  Prussic  acid  is  com- 
posed of  equal  volumes  of  hydrogen  and  cyanogen  ?  What 
follows  from  it,  with  regard  to  its  composition  by  weight  ? 

[§  93.]  With  what  other  substances  does  cyanogen 
yet  combine  ?  What  properties  have  all  these  compounds  ? 
What  is  a  compound  of  cyanogen  and  sulphur  called  ? 
What  properties  has  it  ? 

[§  94.]  In  how  many  different  proportions  does  carbon 
combine  with  chlorine  ?  What  are  the  compounds  called  ? 

[§  95.]  What  is  the  chemical  composition  of  sulphu- 
rel  of  carbon  1  By  what  process  can  carbon  and  sulphur 
be  made  to  combine  1  (Explain  the  process  represented 
in  Fig.  CVIII). 

[§  96.]  What  are  the  leading  properties  of  sulphuret 
of  carbon  ?  Why  must  sulphuret  of  carbon  be  distilled  at 
so  low  a  heat  as  1 10  degrees  Fahrenheit  1  What  is  the 
specific  gravity  of  sulphuret  of  carbon  1  What  is  its  great 
volatility,  the  cause  of? 

What  are  the  principal  binary  and  ternary  combina- 
tions of  Carbon  1 

B.     QUESTIONS  ON  SULPHUR. 

[§  97.     What  is  the  chemical  equivalent  of  sulphur? 
Where  does  sulphur  occur  ?     Where  does  it  abound  ? 
In  what  countries  particularly  has  it  been  discovered  ? 


168  RECAPITULATION 

Where  is  sulphur  yet  contained  ? 

By  what  process  can  sulphur  be  purified  from  stones 
and  other  earthy  substances  with  which  it  is  mixed  ? 

[§  98.]  What  are  the  principal  properties  of  sulphur  ? 
What  is  its"  specific  gravity?  How  is  roll-brim,stone, 
obtained,  which  occurs  in  commerce  1  What  becomes 
of  sulphur,  when  in  a  state  of  fusion  it  is  poured  into  wa- 
ter ?  For  what  is  it  then  used?  What  are  the  principal 
applications  of  sulphur  ? 

[§  99.]  In  how  many  different  proportions  does  sul- 
phur combine  with  oxygen  ?  What  are  the  products  ? 
Which  of  these  combinations  are  the  most  remarkable 
ones? 

[§  100.J  What  is  the  chemical  composition  of  sul- 
phurous acid  ?  Where  does  this  compound  occur  ?  By 
what  means  may  it  also  be  produced  in  a  state  of  great 
purity  ? 

How  is  this  process  explained  ? 

[§  101.]  What  are  the  principal  properties  of  sulphu- 
rous acid  ?  What  do  you  understand  by  liquid  sulphurous 
acid  ?  How  does  this  acid  act  upon  vegetable  colors  ? 
For  what  purpose  is  it  chiefly  used  ? 

[§  102.]  What  is  the  chemical  composition  of  sulphu- 
ric acid?  What  degree  of  oxygenation  of  sulphur  is  sul- 
phuric acid  ?  Where  does  it  occur  ? 

How  many  different  sorts  of  sulphuric  acid  occur  in 
commerce  ?  What  are  their  names  ?  From  what  is  the 
first,  and  from  what  is  the  second  obtained  ? 

Explain  the  process  by  which  the  oil  of  vitriol  is  procured  ? 

How  is  hydro-sulphuric  acid  (or  the  common  sulphuric  acid 
of  commerce)  manufactured  ? 

How  is  this  complicated  process  explained  ?  (Let  the  pu- 
pil explain  the  table  on  page  145). 

[§  103.]  What  are  the  characterizing  properties  of 
oil  of  vitriol  ?  What  are  the  properties  of  sulphuric  acid  ? 

[§  104.]  What  are  the  principal  applications  of  sul- 
phuric acid  ? 


OF    CHAPTER    II.  Jgg 

[§  105.]  In  how  many  different  proportions  does  sul- 
phur combine  with  hydrogen  ?  What  are  the  compounds  ? 

[§  106.]  What  is  the  chemical  composition  of  sulphu- 
retted hydrogen? 

Where  does  it  occur  ?  Where  is  it  spontaneously  pro- 
duced (or  given  off)  ?  How  may  it  be  obtained  for  the 
sake  of  experiment  ?  By  what  other  means  may  it  be  ob- 
tained in  abundance  ?  How  is  this  process  explained? 

[§  107.]  What  are  the  properties  of  sulphuretted  hy- 
drogen ?  For  what  is  sulphuretted  hydrogen  particularly 
remarkable?  By  what  substance  is  it  decomposed? 
What  does  this  explain  ? 

[§  108.]     With   what  other  substances   does  sulphur 

combine  ?     Is  sulphur  known  to  combine  with   nitrogen  ? 

What  are  the  principal  binary  combinations  of  sulphur  ? 

C.     QUESTIONS  ON  SELENIUM. 

[§  109.]  What  is  the  chemical  equivalent  of  seleni- 
um ?  Where  does  it  occur  ?  What  are  its  properties  ? 

In  how  many  different  proportions  does  it  combine  with 
oxygen  ?  Name  the  compounds.  What  compounds  does  it 
form  with  hydrogen  ?  In  how  many  different  proportions  does 
it  unite  with  sulphur  ?  What  are  the  compounds  called  ? 

D.     QUESTIONS  ON  PHOSPHORUS. 

[§  110.]  Has  phosphorus  as  yet  been  found  in  nature 
in  its  simple  form  ?  From  what  is  it  chiefly  obtained  ? 

Describe  the  process  by  which  phosphorus  is  obtained.  Ex- 
plain this  process. 

[§  111.]  What  properties  distinguish  phosphorus  ob- 
tained in  the  manner  you  have  ju?t  described  ? 

Why  is  it  necessary  to  keep  phosphorus  under  water  ? 
What  does  phosphorus  emit  in  contact  with  air  ? 

With  what   liquids  does  phosphorus   readily  combine  ? 

15 


170  RECAPITULATION 

How  much  oxygen  is  phosphorus  capable  of  taking  up  ? 
For  what  is  it  used  ? 

[§  112.]  In  how  many  different  proportions  does  phos- 
phorus combine  with  oxygen  1  What  are  the  products 
called  ? 

[§  1 13.]  What  is  the  chemical  composition  of  phos- 
phoric acid  ?  Where  does  this  composition  occur  ?  How 
may  it  be  obtained  by  art  1  (Explain  the  experiment  and 
process  represented  in  Fig.  CX). 

[§  114.]  What  are  the  characterizing  properties  of 
phosphoric  acid  ? 

[§  115.]  In  how  many  different  proportions  does  phos- 
phorus unite  with  hydrogen  ?  What  are  the  products 
thence  obtained  called  ? 

What  is  the  composition  of  proto-phosphuretted  hydro- 
gen 1  What  is  the  composition  of  per-phosphuretted  hy- 
drogen ? 

[§  116.]  By  what  process  is  per-phosphuretted  hydro- 
gen obtained?  (Explain  the  experiment  represented  in 
Fig.  CXI).  How  is  this  process  explained  ? 

What  takes  place  when  the  gas,  as  it  is  extricated,  is  allow- 
ed to  escape  from  under  the  surface  of  the  alkaline  solution 
into  the  air  ? 

[<§  117.]     What  properties  does  phosphu retted  hydrogen 


How  is  proto-phosphuretted  hydrogen  produced  ?  To  what 
are  its  properties  similar  ?  What  takes  place  when  the  gas  is 
mixed  with  oxygen,  and  an  electric  spark  is  applied  to  the 
mixture  ? 

What  beautiful  experiment  may  be  made  with  water,  phos- 
phorus, zinc,  and  sulphuric  acid  ?  How  is  this  experiment  ex- 
plained ? 

[§  118.]  With  what  other  substances  does  phosphorus 
yet  unite  ? 

What  are  the  most  important  binary  combinations  of 
Phosphorus  ? 


OF    CHAPTER   II.  171 

E.  QUESTIONS  ON  BORON. 

What  is  the  chemical  equivalent  of  boron  ? 

[§  119.]     Is  this  element  found  in  its  simple  state? 
How  then  is  it  obtained  ? 
Explain  the  process. 
What  are  the  properties  of  boron  ? 
What  is  the  product  of  the  combustion  of  boron  ? 

[§  120.]  What  is  the  chemical  composition  of  boracic 
acid  ?  Are  there  any  other  combinations  of  boron  with 
oxygen  ?  In  what  form  is  boracic  acid  generally  obtain- 
ed ?  Where  is  it  found  ?  How  may  it  be  produced  by 
art? 

Explain  this  process. 

[§  121.]     What  are  the  properties  of  boracic  acid  ? 
VViih  what  other  substances  does  boron  yet  combine  ? 

F.  QUESTIONS  ON   IODINE. 

[§  122.]  What  is  the  chemical  equivalent  of  iodine  ? 
Does  this  element  occur  in  its  simple  form  ?  With 
what  substances  is  it  found  combined  ?  Where  has  it 
lately  been  discovered?  From  what  substances  is  it  com- 
monly extracted  ? 

Describe  the  process. 

[§  123.]  What  are  the  principal  properties  of  iodine  ? 
What  sort  of  compound  does  it  form  in  combination  with 
starch  ?  .  For  what  purposes  is  it  principally  used  ? 

[§>  124.]  In  how  many  proportions  does  iodine  com- 
bine with  oxygen  ?  What  is  the  product  of  this  combi- 
nation called  ?  By  what  means  is  it  obtained  ? 

[§  125.]  What  is  a  combination  of  iodine  with  hydro- 
gen called  ?  What  is  its  chemical  composition  ?  How  is 
this  combination  effected  ? 

What  are  the  properties  of  hydriodic  acid  ? 


172  RECAPITULATION 

[§  126.]  With  what  other  substances  does  iodine  com- 
bine ? 

What  are  the  principal  binary  combinations  of  Iodine  1 
G.     QUESTIONS  ON  BROMINE. 

[$   127.]     What  is  the  chemical  equivalent  of  bromine  ? 
By  whom  was  it  discovered  1     How  may  it  be  obtained  1 
Explain  the  process. 

[§   128.]     What  are  the  principal  properties  of  bromine  ? 

[§  129.]  To  what  compound  does  bromine  combine 
with  oxygen  ?  What  is  the  chemical  composition  of  this 
compound  ?  In  how  many  different  proportions  does  it 
combine  with  hydrogen  ?  What  are  the  two  compounds 
called  ?  Which  of  the  two  is  the  most  remarkable  ? 
What  are  its  properties  ? 

With  what  other  substances  does  bromine  yet  combine  ? 

What  are  the  -principal  binary  combinations  of  Bromine  1 
H.     QUESTIONS  ON  SILICON  (SILICIUM). 

[§  130.]  What  is  the  chemical  equivalent  of  silicon  ? 
By  whom  was  this  substance  discovered?  With  what 
other  substances  was  it  formerly  known  only  to  be  com- 
bined 1  By  what  means  may  it  be  separated  from  these 
combinations?  What  are  its  properties? 

[§  131.]     In  how   many  proportions  does  it   combine 
with  oxygen  ?     What  is  the  compound  called  ?     What  is 
its  chemical  composition  ?     Where  is  it  found  ? 
How  may  silex  be  obtained  by  art  ? 

[§  132.]  What  are  the  principal  properties  of  silex? 
What  does  it  form  when  combined  with  hydrogen  ?  In 
what  consists  the  principal  application  of  silex  ? 

In  what  fossils  does  silicious  earth,  or  silex,  principally  oc- 
cur ?  [Let  the  pupil  at  first  merely  enumerate  the  fossils, 
without  describing  them]. 


OF    CHAPTER    II.  173 

What  are  the  properties  of  Rock  or  Mountain  Crystal  ? 

What  are  the  principal  properties  of  the  rfmaihystt 

What,  those  of  common  quartz?  For  what  purposes  is 
common  quartz  used  ? 

What  are  the  principal  properties  of  Flint  ?  For  what  pur- 
poses is  it  used  ?  To  what  species  of  stone  belong  Jlgate, 
Choice  'on,  Jaspis,  Carnelion,  Chrysoprast  ? 

What  are  the  properties  of  Pumice?  What  sort  of  product 
is  it?  Where  is  it  found  ?  For  what  is  it  used? 

What  sort  of  natural  product  is  sand  ?  Where  is  it  found  ? 
For  what  purposes  is  it  used  ? 

In  what  other  substances  is  silicious  earth  contained  ?  What 
sort  of  substance  is  tripoli,  or  rotten  stone  $  Where  is  it 
found  ?  For  what  is  it  used  ? 

I.     QUESTIONS  ON  FLUORINE. 

[§  133.]  Is  the  existence  of  Fluorine  as  yet  satisfac- 
torily proved  ?  By  whom  was  this  substance  first  suppos- 
ed to  exist  1  To  what  elements  is  it  supposed  to  be  anal- 
ogous ?  What  substance  is  it  supposed  to  form  with 
hydrogen  ? 

[§  134.]  What  is  the  chemical  equivalent  of  fluoric 
acid  ?  By  what  means  \sjlvoric  acid  obtained  1 

In  what  state  is  fluor-spar  obtained  ?  What  does  it  assist? 
What  is  fluor-spar  supposed  to  be  ? 

[§  135.]  What  are  the  properties  of  fluoric  acid  1 
What  properties  do  its  vapors  possess  ?  What  is  this  the 
reason  of?  What  takes  place  when  lime  is  thrown  into  a 
solution  of  it  in  water  1 

What  peculiar  power  does  it  possess  in  consequence  of 
its  affinity  for  the  principal  ingredient  of  glass  t  How 
may  plates  of  glass  be  etched  by  fluoric  acid  1 

[§  136.]  With  what  other  substances  does  fluorine 
yet  combine?  What  are  the  products?  What  are  the 
properties  of  fluoric  acid?  What  are  the  properties  of 
fluoride  of  silicon  similar  to? 

What  are  the  most  important  binary  combinations  of 
Fluorine  ? 

15* 


174  OF    THE    METALS. 


CHAPTER    III. 

OP  THE  METALS. 

Preliminary  Remarks. 

§  137.  Several  attempts  have  been  made  to  fix  upon 
the  general  characteristics  of  metals ;  their  properties, 
however,  are  so  various  and  relative,  that  we  can  only  ap- 
proximate more  or  less  to  a  satisfactory  result.  With  this 
view  on  the  subject  it  may  be  said  that  all  metals  are  more 
or  less  distinguishable  by  the  following  properties  : 

1.  By  a  peculiar  lustre,  called  the  metallic  lustre,  which 
is  owing  to  their  capacity  of  reflecting  light. 

2.  By  being  generally   good    conductors  of  heat  and 
electricity.     They   are,  moreover,  commonly  electro-posi- 
tive bodies  ;  for  when  in  a  combined  state  with  other  sub- 
stances, they   are   submitted  to  the  action   of  a  galvanic 
battery   (see  Figs.  LIX  and  LX,  pages  40  and  4 1), these 
combinations  are  again  dissolved  into  their  elements,  and 
the  pure  metal  is  always  found  to  adhere  to  the  negative 
pole.     (Compare  the  remarks  in  the  Introduction,  page  41 .) 

3.  By  their  opacity,  to  which  hitherto  but  few  appa- 
rent exceptions  have  been  found. 

§  138.  All  metals,  as  far  as  our  experience  goes,  are 
simple  bodies,  or  elements,  all  efforts  to  decompose  them 
having  thus  far  proved  ineffectual.  They  are  in  number 
fortyone. 


OF    THE    METALS. 


175 


22.  Iron, 

23.  Tin, 

24.  Lead, 

25.  Copper, 

26.  Zinc, 

27.  Bismuth, 

28.  Cobalt, 

29.  Antimony, 

30.  Arsenic, 

31.  Manganese, 

32.  Tellurium, 

33.  Titanium, 

34.  Cerium, 

35.  Uranium, 

36.  Columbium, 

37.  Tungsten, 

38.  Cadnium, 

39.  Chromium, 

40.  Molybdenum, 

41.  Vanadium. 


1.  Potassium, 

2.  Sodium, 

3.  Lithium, 

4.  Calcium, 

5.  Barium, 

6.  Strontium, 

7.  Magnesium, 

8.  Yttrium, 

9.  Alumium, 

10.  Glucinum  (Berillium), 

11.  Zirconium, 

12.  Thorium, 

13.  Mercury. 

14.  Silver, 

15.  Gold, 

16.  Platinum, 

17.  Palladium, 

18.  Rhodium, 

19.  Iridium, 

20.  Osmium, 

21.  Nickel, 

§  139.  These  metals  vary  from  each  other  in  color, 
hardness,  brittleness,  ductibility,  and  fusibility.  All  of 
them,  however,  have  a  greater  or  less  affinity  for  oxygen, 
and  combine  with  it  under  the  following  circumstances  : 

1.  When  exposed  to  the  atmosphere. 

2.  When  brought  in  contact  with  water   (which  con- 
tains oxygen),  or  any  of  the  acids  formed  by  the  combina- 
tion of  oxygen.     For  this  purpose  concentrated  sulphuric 
and  nitric  acid  are  commonly  used. 

Most,  metals  when  exposed  to  the  air  or  to  moisture  lose 
their  metallic  lustre,  tenacity,  and  other  apparent  properties  of 
metals.  They  then  crumble  to  powder,  or  soil  the  fingers, 
having  at  the  same  time  increased  in  weight.  This  change  is 
occasioned  by  the  metals  having  combined  with  the  oxygen  of 
the  atmosphere  or  the  water,  or,  in  other  words,  by  its  having 
been  changed  into  an  oxide  (see  classification  of  bodies,  page 
38).  The  increase  of  weight  is  of  course  proportions!  to  the 
quantity  of  oxygen  taken  up  in  the  combination.  (See  there- 
mark  §  9,  to  the  experiment  represented  in  Fig.  LXVI,  page  54). 


176  OF    THE    METALS. 

Among  the  various  metals  iron  especially  absorbs  oxygen 
from  the  air  and  from  moisture  ;  and  is  by  this  means  convert- 
ed into  a  friable  substance  which  collects  on  its  surface.  This 
substance,  which  is  an  oxide  of  iron,  is  called  rust.  In  order, 
therefore,  to  prevent  metals,  and  especially  iron,  from  rusting, 
it  is  necessary  to  keep  them  from  the  atmosphere.  Sir  Hum- 
phrey Davy  proposed  also  galvanic  electricity  as  a  preventive 
against  the  oxydation  of  metals.  Thus,  copper  is  preserved 
from  combining  with  the  oxygen  of  the  atmosphere  by  bringing 
it  in  contact  with  iron,  only  y^  part  its  size.  The  reason  is 
this.  When  copper  andiron  are  placed  upon  one  another,  the 
copper  becomes  negatively  electric  (see  Nat.  Phil.  Chap.  IX), 
in  which  state  it  cannot  attract  the  oxygen  of  the  atmosphere, 
which  is  itself  a  negatively  electric  substance  ;  but  must  repel 
it,  according  to  the  laws  of  electricity.  Steel  instruments  are 
kept  in  silver  paper,  made  of  a  mixture  of  tin  and  zinc,  for  a 
similar  reason.  In  a  great  many  cases,  however,  galvanic 
electricity  favors  the  oxydation  of  metals. 

••    §   140.     Oxygen  is  not  the  only  substance  with  which 
metals  are  known  to  combine.     They  unite  also, 

1st.  With  Carbon.  The  products  of  these  combina- 
tions are  called  carburets.  They  do  not  occur  in  nature, 
and  are  produced  only  by  the  fusion  of  the  oxides  of  met- 
als in  contact  with  charcoal  and  other  substances  contain- 
ing carbon. 

2d.  With  sulphur.  The  result  of  these  combinations 
are  termed  sulphides.  They  occur  abundantly  in  na- 
ture, and  form  by  far  the  most  important  ores  of  copper, 
lead,  tin,  antimony,  silver  and  quicksilver. 

3d.  With  Chlorine.  These  combinations  are  called 
chlorides,  and  are  large  products  of  nature.  To  this  class 
belong  the  chloride  of  Potassium,  sodium,  calcium,  mag- 
nesium, lead,  &c. 

4th.  With  Cyanogen,  forming  what  are  called  cyanides. 
These  combinations  are  mere  products  of  art. 

5th.  With  Silicon,  forming  silicides. 

6th.  With  Fluoride,  forming  fluorides,  which  are  fre- 
quently found  in  nature,  particularly  fluoride  of  calcium 
(fluor  spar),  fluoride  of  yttrium,  &c. 

Besides  these  combinations,  many  metals  unite  yet  with 


OF    THE    METALS.  177 

hydrogen,  selenium,  phosphorus,  boron,  and  iodine  ;  form- 
ing respectively  hydrates,  selenides,  phosphorides,  borides, 
and  iodides.  But  •  we  shall  not  stop  to  describe  these, 
intending  to  treat  only  of  the  most  remarkable  and  useful 
metallic  combinations. 

§  141.  Alloys  of  metals.  Metals  frequently  combine 
with  one  another  ;  these  combinations  are  called  alloys  ; 
but  the  combinations  of  quicksilver  with  other  metals  have 
received  the  special  appellation  of  amalgams.  The  alloys 
of  metals  have  each  a  peculiar  color,  according  to  the 
proportion  of  the  metals  in  which  they  are  compounded. 
They  are  generally  harder,  though  easier  fusible  than  ei- 
ther one  of  the  metals  of  which  they  are  compounded. 

§  142.  Of  two  metals  which  have  different  degrees  of 
fusibility  and  no  particular  chemical  attraction  for  each 
other,  one  may  be  made  to  melt  (reduced  to  the  liquid 
state),  while  the  other  remains  yet  in  the  solid  state.  This 
is,  for  instance,  the  case  with  the  ores  of  copper  and  lead, 
tin  and  copper,  bismuth  and  cobalt,  &c.  On  account  of  this 
property,  fusion  is  a  means  of  refining  ores,  the  more  fusi- 
ble metal  being  by  this  means  liquefied  and  separated  from 
the  other,  which  remains  in  a  state  of  solidity. 

§  143.  Metals  which  easily  melt  are  capable  of  ad- 
vancing the  fusion  of  other  metals  for  which  they  have  a 
strong  chemical  affinity.  Upon  this  property  is  founded 
the  process  of  soldering.  This  consists  in  uniting  two 
pieces  of  the  same,  or  different  metals,  by  means  of  a  third 
metal  which  is  more  fusible  than  either  of  them.  To  give  an 

EXAMPLE  —  To  solder  tin  ware,  tinkers  make  use  of  a  com- 
position- (that  is,  of  a  solder)  made  of  equal  parts  of  tin  and 
lead. 

Cast  iron  is  soldered  either  by  copper,  silver,  or  tin,  or  also 
by  a  mixture  of  copper  and  tin. 

Copper  and  brass  are  soldered  by  a  mixture  of  5  parts  of 
silver,  6  parts  of  brass,  and  2  parts  of  zinc. 

Zinc  is  soldered  by  a  mixture  of  lead  and  tin. 

Platinum  by  fine  gold. 

Gold  by  a  mixture  of  gold  and  silver ;  and 

Silver  by  a  mixture  of  silver  and  copper. 


178  OF    THE    METALS. 

§  144.  Another  process  of  art,  founded  on  the  natu- 
ral attraction  which  exists  between  some  of  the  metals, 
is  the  covering  of  one  metal  by  another.  As  an  example 
we  will  mention  the  tinning  of  vessels  made  of  sheet  iron  ; 
the  gilding  and  silvering  by  means  of  amalgams  with 
which  the  substance  to  be  gilded  or  silvered  is  merely 
covered  as  with  a  pigment ;  finally  the  plating  of  brass, 
steel,  or  copper  ware,  with  gold,  silver,  or  platinum,  where 
one  hard  metal  is  rolled  upon  another,  and  remains  upon 
it  merely  by  the  natural  force  of  attraction,  without  any 
solder  between  them. 

§  145.  We  have  already  said  that  few  of  the  metals 
are  found  in  nature  in  their  simple  form  ;  but  general- 
ly combined  with  sulphur,  oxygen,  the  acids,  or  earths, 
in  which  state  they  are  called  metallic  ores.  They  oc- 
cur more  or  less  in  all  quarters  of  the  globe,  but  partic- 
ularly in  mountainous  districts  and  in  the  neighborhood 
of  volcanos.  They  are  generally  bedded  in  strata,  ex- 
tending sometimes  several  miles  in  length,  which  by  the 
miners  are  called  veins.  Hence  the  common  phrase  of 
the  miners,  '  to  strike  a  new  vein.'  In  these  veins  the 
metals  are  most  commonly  found  combined  with  those 
substances  we  have  just  named,  which  on  this  account 
are  called  mineralizers.  Sulphur  being  most  abundantly 
found  combined  with  the  metals,  is  therefore  called  a  min- 
eralizer  of  them.  But  there  are  metals  which  are  some- 
times found  in  their  simple  form,  and  are  then  said  to  be 
native  metals.  In  this  state  gold  and  silver  are  frequently 
found  in  North  and  South  America.  The  gold  of  South 
Carolina  and  Georgia,  for  instance,  is  so  pure  that  without 
alloy  it  cannot  very  well  be  worked.  The  silver  mines  of 
Potosi,  in  South  America,  have  been  known  to  yield  na- 
tive silver,  in  lumps  of  forty  or  fifty  pounds  in  weight. 

§  146.  The  substances  with  which  the  metals  are  com- 
bined (the  mineralizers)  being  so  different  from  each  oth- 
er in  their  chemical  composition,  it  is  evident  that  differ- 
ent methods  must  be  employed  for  different  ores,  in  order 
to  extricate  the  pure  metal  from  them.  This  process  of 
extracting  the  pure  metal  from  the  ore  is  called  the  reduc- 


OP    THE    METALS.  179 

tion  of  the  mdals.  Three  means  are  principally  resorted 
to  for  this  purpose, 

1st.  The  roasting  of  metals,  which  consists  in  placing 
metallic  ores  upon  a  wood  or  coal  fire,  and  heating  them  to 
redness.  By  this  means  sulphur  and  other  substances 
which  are  mixed  with  the  metals  are  separated.  But  there 
are  ores  which  do  not  require  to  be  roasted. 

2d.  The  smelting  of  ores,  or  the  melting  out  of  the  met- 
als from  the  ore.  For  this  purpose  the  ore  and  charcoal 
are  mixed  together  in  a  furnace,  and  in  this  state  intense- 
ly heated,  by  which  means  the  oxygen  which  is  combined 
with  the  metal,  unites  by  elective  affinity  with  the  burning 
charcoal,  for  which  it  has  a  most  powerful  affinity,  setting 
thereby  the  metal  free.  When  the  metal  is  thus  extricated 
from  the  ore,  care  is  taken  to  cover  its  surface  with  a 
melted  mass  of  some  earthy  or  alkaline  substance,  called 
the  flux,  to  prevent  its  subsequent  oxydation  in  contact 
with  the  atmospheric  air. 

3d.  The  refining  of  metals,  which  process  has  already 
been  described  in  §  142,  page  177. 

§  147.  Before  we  go  on  to  treat  of  the  different  met- 
als and  their  properties,  it  will  be  well  to  say  a  few  words 
on  the  similar  properties  of  some  of  them,  which  enable 
us  to  form  them,  as  it  were,  into  classes.  Thus  : 

Potassium,  sodium,  lythium,  calcium,  barium,  and  stron- 
tium, are  generally  called  the  alkaline  metals  ;  because  in 
combination  with  oxygen  they  form  respectively  the  fixed 
alkalies,  potash,  soda,  lithia,  lime,  baryta,  and  strontia. 
These  metals  have  all  the  strongest  affinity  for  oxygen, 
absorb  it  at  all  times  from  the  atmosphere,  and  retain  it  at 
the  highest  degree  of  heat.  Their  oxides,  (the  alkalies 
which  we  have  just  enumerated)  have  all  a  hot,  bitter, 
caustic  taste,  are  soluble  in  water,  change  blue  vegetable 
colors  into  green,  and  yellow  colors  into  brown. 

Magnesium,  yttrium,  allumium,  glacinutn,  zirconium, 
thorium  are  called  earthy  metals,  because  in  combination 
with  oxygen  they  form  the  earths  magnesia,  glucina,yttria, 
alumia,  zirconia,  and  thoria. 

The  nine  metals,  mercury,  silver,  gold,  platinum,  palla- 


180  POTASSIUM. 

dium,  iridium,  osmium,  and  nickel,  are  commonly  called  the 
noble  metals  ;  because  they  do  not  easily  undergo  any 
change  or  combine  with  oxygen. 

Of  the  remaining  twenty  metals,  iron,  lead,  tin,  copper, 
zinc,  bismuth,  cobalt,  antimony,  arsenic,  manganese,  telluri- 
um, titanium,  cerium,  uranium,  columbium,  tungsten,  cad- 
mium, chromium,  molybdenum,  and  vanadium,  the  first  five 
(iron,  lead,  tin,  copper  and  zinc)  are  the  most  useful  to 
man,  and  are  most  generally  employed  in  the  arts. 

We  will  now  proceed  to  describe  each  metal  and  its 
principal  binary  combinations  in  the  same  order  as  we 
have  just  enumerated  them. 

A.     OF  THE  six  ALKALINE  METALS,  POTASSIUM,  SODIUM, 
LITHIUM,  CALCIUM,  BARIUM,  AND  STRONTIUM. 

1.     Potassium. 
Chemical  Equivalent  =  40. 

§  148.  Potassium  is  a  metal  which  was  first  obtained 
by  Humphrey  Davy  from  the  decomposition  of  a  substance 
called  hydrate  of  potash  (see  the  next  section)  through 
the  agency  of  a  strong  galvanic  battery.  It  may  also  be 
obtained  in  larger  quantities,  by  heating  hydrate  of  potash 
with  iron  filings  in  a  gun  barrel. 

The  first  process  requires  a  galvanic  battery  composed  of 
at  least  200  double  plates,  of  4  inches  square.  The  hydrate 
of  potash  must  be  slightly  moistened  (to  increase  the  conduct- 
ing power  of  electricity)  and  placed  between  two  plates  of 
platinum  connected  with  the  two  poles  of  the  apparatus.  The 
substance  will  soon  undergo  fusion,  when  the  oxygen  of  which 
it  is  compounded,  will  separate  at  the  positive  pole,  and  the 
pure  metal  (Potassium)  will,  in  little  globules,  collect  near  the 
negative  pole  of  the  battery. 

For  the  decomposition  of  hydrate  of  potash  by  the  action  of 
heated  iron-filings,  by  which  means  potassium  is  obtained  in 
larger  quantities,  we  are  indebted  to  the  combined  researches 
of  Gay-Lussac  and  Thenard. 


POTASSIUM. 


181 


The  apparatus  employed  for  this  purpose  is  represented  in 
Fig.  CXII. 


a 


Fig.  XCII.  It  consists  of  a  very  strong  gun-barrel,  a  b  c, 
which  must  be  curved  as  represented  in  the  figure.  Towards 
one  end  c,  of  this  barrel,  it  must  be  tapering  to  a  smaller  open- 
ing, and  the  whole  space  between  a  and  6,  must  be  covered 
with  a  lute  of  infusible  clay,  which  may  be  made  of  5  parts  of 
sand  and  1  of  potters'  clay.  Into  this  barrel,  between  6  and  c, 
introduce  some  clean  iron-filings,  and  between  a  and  6,  pieces 
of  solid  hydrate  of  potash.  The  barrel  must  afterwards  be 
corked  and  in  a  provided  with  a  safety  tube,  whose  lower  end  (as 
is  represented  in  the  figure)  must  be  immersed  into  a  vessel  rf, 
filled  with  mercury.  To  the  smaller  end  of  the  barrel,  a  short 
piece  (e)  of  copper  is  accurately  ground,  which  fits  again  into 
a  receiver/,  made  of  the  same  metal.  This  receiver  is  also 
provided  with  a  safety  tube  g-,  which  dips  below  the  surface  of 
mercury  contained  in  the  vessel  h.  A  strong  heat  should 
now  be  raised  in  the  furnace,  until  the  barrel  between  6  and  c, 
becomes' white  hot;  the  other  parts  of  the  barrel  being  all  this 
time  kept  cool  by  wet  rags  tied  around  them.  The  hydrate  of 
potash  in  the  part  a  6,  of  the  barrel,  may  now  be  made  to  melt 
by  burning  charcoal  contained  in  a  movable  cage  t,  when  in 
consequence  of  the  inclination  of  the  barrel  it  will  flow  upon 
the  ignited  iron  filings,  in  the  part  6  c,  by  which  means  a  large 
quantity  of  hydrogen  (the  product  of  the  decomposition  of 
hydrate  of  potash),  will  be  given  off  and  escape  through  the 
safety  tube  g.  The  movable  cage  must  now  be  removed  for  a 
little  while,  until  the  evolution  of  the  gas  ceases ;  after  which 

16 


182  POTASSIUM. 

it  must  be  again  put  in  its  place  ;  and  this  operation  must  be 
continued  until  no  more  gas  is  evolved.  The  hydrogen 
of  the  hydrate  of  potash  will  then  have  escaped  through  the 
safety  tube,  and  the  potassium  in  an  oxidized  state,  will  have 
combined  with  the  filings  in  the  barrel.  But  as  strongly 
heated  iron  filings  have  a  stronger  affinity  for  oxygen  than 
potassium,  an  intense  heat  produced  in  the  furnace  will  now 
be  sufficient  to  separate  the  potassium  from  them,  and  to 
collect  the  metal  nearly  pure  in  the  copper  receiver  f,  and  the 
short  tube  e. 

When  these  vessels  are  sufficiently  cooled  they  must  be  re- 
moved and  filled  with  naphta,  to  give  the  potassium  contained  in 
them  a  coating,  which  prevents  its  oxidation  in  contact  with 
atmospheric  air.  The  naphta  being  now  emptied  again,  the  ves- 
sels are  stopped  with  cork  until  they  are  sufficiently  cool  for 
the  purpose  of  handling.  The  pure  potassium  may  afterwards 
be  taken  out  and  preserved  in  stopped  phials,  under  rectified 
naphta. 

Asa  small  portion  of  potassium  will  always  collect  at  the 
lower  end/,  of  the  barrel,  it  will  be  well  to  stop  the  barrel  it- 
self with  corks  as  soon  as  the  copper  barrel  and  receiver  are 
removed  from  it.  When  sufficiently  cooled  some  naphta 
must  be  suffered  to  pass  through  it,  to  prevent  the  oxidation 
of  whatever  portion  of  the  metal  may  have  collected  in  it, 
which  may  afterwards  be  collected  and  preserved  as  above 
stated. 

If  at  any  time  during  the  process  gas  should  escape  through 
the  safety  tube  d,  instead  of  g,  it  is  a  sign  that  a  piece  of  po- 
tassium has  lodged  between  c  and  e,  to  remove  which  it  is  only 
necessary  to  apply  some  burning  charcoal  to  the  spot,  which 
will  liquefy  the  potassium,  and  enable  the  process  to  go  on 
regularly. 

The  potassium  thus  obtained  is  less  pure  than  that  which  is 
procured  by  galvanic  electricity  ;  but  it  is  obtained  in  much 
larger  quantities  and  at  a  comparatively  less  expense.  The 
only  difficulty  consists  in  producing  a  sufficiently  high  heat  for 
the  iron  filings  to  decompose  the  oxide  of  potassium  without 
melting  the  barrel,  and  it  is  on  that  account  that  the  part  d  c, 
which  is  to  be  heated  in  the  furnace,  must  be  covered  with  a 
lute  of  infusible  clay. 

§  149.  Properties  of  Potassium.  Potassium,  obtained 
by  either  of  the  processes  just  described,  is  at  the  ordinary 
temperature  of  the  atmosphere,  of  a  soft,  solid  consistency, 
and  easily  moulded  between  the  fingers.  Its  color  is  that 


POTASSIUM.  133 

of  tin  ;  it  has  a  strong  metallic  lustre,  is  perfectly  opaque, 
and  a  good  conductor  of  heat  and  electricity.  It  is  spe- 
cifically lighter  than  water,  (its  specific  gravity  being  only 
0.865,  that  of  water  being  I),  fuses  at  150°  Fahrenheit, 
and  burns  with  a  white  flame  when  heated  in  contact  with 
air.  It  decomposes  water  at  the  common  temperature  of 
the  air,  by  combining  with  its  oxygen,  for  which  it  has  the 
strongest  affinity  of  any  substance  known.  On  this  ac- 
count (because  it  would  absorb  the  oxygen  from  the  at- 
mosphere) it  is  necessary  to  keep  it  under  naphta. 

Combination  of  Potassium  with  Oxygen. 

§  150.  Potassium  forms  three  different  combinations 
with  oxygen,  viz.  :  Sub-oxide,  Protoxide,  and  Peroxide 
of  Potassium.  The  most  remarkable  among  these  is  the 
protoxide  of  potassium,  commonly  known  by  the  name  of 

Potash,  or  Potassa. 

It  is  composed  of  1  equivalent  of  Potassium  =40 
1    equivalent   of    oxygen  =    8 


Consequently,  chemical  equivalent  of  Potash  =  48. 

This  substance  occurs  in  all  three  kingdoms  of  nature, 
combined  with  the  acids  and  in  some  of  the  fossils,  such 
as  fluor-spar,  basalt,  granite,  &,c.  The  purest  potash  is 
obtained  by  burning  potassium  in  dry  air.  It  is  of  a 
greyish-white  color,  hard,  brittle,  and  easily  soluble  in 
water.  It  is  very  caustic,  and  destroys  animal  and  vege- 
table substances. 

The  potash  of  commerce  is  obtained  by  the  incineration 
(burning,  to  ashes)  of  vegetable  substances,  wherefore  it  is 
called  the  vegetable  alkali.  These  ashes  are  afterwards  boiled 
down  in  pots,  whence  the  name  of  Potash.  The  purest  is  call- 
ed Pearl-ash.  Potash  unites  with  water  to  hydrate  of  potash 
(caustic  potash),  which  is  easily  dissolved  in  water,  and  com- 
bined with  fat  or  oil  forms  soap,  a  product  of  universal  useful- 
ness. 

<§>  151.  The  hydrate  of  potash  is  a  white  solid  mass, 
which  melts  at  a  red  heat  and  emits  white  caustic  vapors. 
It  is  obtained  from  a  solution  of  a  salt  called  carbonate 


184  POTASSIUM. 

of  potash,  in  10  or  12  parts  of  distilled  water.  A  silver 
plated  kettle  must  be  used  for  this  purpose,  as  other  metals 
are  affected  by  the  solution.  When  the  liquid  is  boiling 
J  part  of  fresh  burnt  marble  or  lime  must  be  added  in  a 
state  of  powder,  and  after  being  repeatedly  stirred  up  with 
it,  the  solution  must  be  evaporated  to  dryness. 

§  152.  A  solution  of  hydrate  of  potash  is  termed  caus- 
tic lye.  It  is  either  colorless,  or  of  a  pale  yellow  color  ; 
otherwise  it  is  similar  to  the  hydrate  of  potash. 

Potash,  hydrate  of  potash,  and  caustic  lye,  are  used  in 
various  processes  in  the  arts,  especially  in  the  manufac- 
tory of  glass  (see  Chap.  IV),  in  bleaching,  dyeing  and 
calico-printing. 

§  153.     Potassium  unites  with  chlorine  to 
Chloride  of  Potassium, 

which  is  composed  of  1  equivalent  of  potassium  =40 
1         do.         of  chlorine  =  36 


Consequently,  chem.  equiv.  of  chloride  of  potassium  =  76. 

In  this  state  it  is  found  in  salt  springs,  and  in  sea  water. 
It  may  also  be  produced  by  introducing  small  pieces  of 
potassium  into  chlorine.  The  combination  is  so  rapid 
and  intense  as  to  cause  a  vivid  inflammation,  during  which 
each  grain  of  the  metal  absorbs  about  1  cubic  inch  of  the 
chlorine,  by  which  means  it  is  converted  into  a  white  saline 
body,  which  has  a  bitter  taste,  and  when  mixed  with  4 
parts  of  water,  forms  a  highly  refrigerating  mixture. 

Potassium  unites  also  with  sulphur,  selenium,  and  sodium. 
The  combination  with  sulphur,  which  is  termed  sulphuret  of 
potassium,  is  used  in  medicine. 

Recapitulation  of  the  Principal  Binary  Combinations  of 
Potassium. 

l  C  sub-oxide  } 

\  oxygen  to  <  protoxide  >of 'potassium. 
Potassium  combines  with  /  {peroxide   ^ 

/  chlorine  to  chloride  of  potassium. 
\  sulphur  to  sulphuret  of  potassium. 


SODIUM  185 

2.     Sodium. 

Chemical  Equivalent  =  24. 

§  154.  Sodium  is  produced  from  hydrate  of  soda,  in 
the  same  manner  in  which  potassium  is  obtained  from  hy- 
drate of  potash  (see  §  149).  It  is  a  white  metal,  of  the 
color  of  silver,  which  has  a  strong  metallic  lustre,  and  is, 
like  potassium,  a  good  conductor  of  heat  and  electricity. 
It  is  opaque  and  solid  at  the  common  temperatures  of  the 
atmosphere,  soft  at  160°,  and  becomes  liquid  at  from  180  to 
190  degrees  of  Fahrenheit's  thermometer.  It  decomposes 
water  without  combustion  ;  but  burns  when  only  damped 
with  this  liquid.  Next  to  potassium,  it  has  the  strongest 
affinity  for  oxygen  of  any  substance  known. 

Combination  of  Sodium  with  Oxygen  —  Oxide  of  Sodium, 
or  Soda. 

Chemical  composition:     1  equivalent  of  sodium  ==24 
I         do.         of  oxygen  =    8 


Consequently,  chemical  equivalent  of  soda  =  32. 

§  155.  Sodium  combines  with  oxygen  in  three  differ- 
ent proportions,  the  products  of  which  are  sub-oxide, 
protoxide,  and  peroxide  of  Sodium.  The  protoxide  of 
sodium,  commonly  called  soda,  occurs  native  in  miner- 
al seams  or  crust,  (mineral  alkali)  combined  with  some  of 
the  acids  from  the  mineral  and  vegetable  kingdoms.  The 
purest  soda  is  obtained  by  the  combustion  of  sodium.  It 
is  a  greyish,  white  mass,  hard,  brittle,  less  fusible  and 
volatile  than  potassium,  and  extremely  caustic.  It  is  solu- 
ble in  water  and  alcohol,  and  in  short,  possesses  all  the  al- 
kaline properties  (see  §  147,  page  179)  in  an  eminent  de- 
gree. It  is  largely  used  in  medicine  and  the  arts. 

§  156.  A  combination  of  chlorine  with  sodium,  called 
chloride  of  sodium,  constitutes  our 

16* 


186  LITHIUM. 


Common   Table  Salt. 

Chemical  composition:     \  equivalent  of  sodium  =  24 
1          do.        of  chlorine  = '36 


Consequently,  chemical  equiv.  of  common  salt=  60. 

It  occurs  in  great  masses  as  parts  of  mountainous  forma- 
tions, or  is  found  in  deserts,  where  the  whole  ground  is 
sometimes  covered  with  crystallized  salt.  In  the  deserts 
of  Barun,  Darfur,  Habesh,  in  the  Highlands  of  Africa, 
in  Central  Asia,  near  the  Caspian  Sea,  in  the  Highlands 
of  Thibet,  in  Peru,  and  Chili.  It  is  also  contained  in  sea 
water,  from  which  it  is  obtained  by  a  variety  of  processes, 
but  particularly  by  boiling  and  evaporating.  It  may  also 
be  obtained  in  its  purest  form,  by  burning  sodium  in  chlo- 
rine ;  or  by  heating  sodium  in  muriatic  acid  gas.  (Hence 
it  is  by  some  chemists  called  muriate  of  soda).  It  is  sol- 
uble in  water  and  in  most  liquids,  crystallizes  in  four-sided 
pyramids  or  cubes,  and  is  one  of  the  most  indispensable 
ingredients  in  the  food  of  man.  It  is  also  used  for  a  vari- 
ety of  chemical  and  medicinal  purposes. 

Recapitulation  of  the  Principal  Binary   Combinations  of 


'incip 
Sodii 


lum. 


Sodium      J  ortfe  en  to  soda. 
combines  with  \  chlorine  to  chloride  of  sodium  or  common  salt. 

3.     Lithium. 
Chemical    Equivalent  =  Id 

§  157.  This  substance  is  likewise  obtained  by  gal- 
vanic electricity,  from  lithia,  an  alkali  which  in  1817  has 
been  discovered  in  several  rare  metals,  in  Tourmaline  (see 
Natural  Phil.  Chap.  X),  and  in  some  mineral  waters.  It 
is  a  white,  solid  mass,  of  a  crystalline  fracture,  and  a  very 
caustic  taste.  It  is  sparingly  soluble  in  water,  and  when 
thrawn  into  alcohol  burns  with  a  purple  flame.  Com- 
bined with  oxygen  it  forms  the 


CALCIUM  187 

Oxide  of  Lithium,  or  Lithia, 

which  is  composed  of  1  equivalent  of  lithium  =  10 
1          do-        of  oxygen  =    8 

Consequently,  chemical  equivalent  of  lithia=  18. 

This  compound  is  soluble  in  water,  with  evolution  of 
heat,  and  possesses  all  the  alkaline  properties  (§  147, 
page  179). 

4.     Calcium. 

Chemical  Equivalent  =  20. 

§  158.  This  is  another  metal  obtained  by  galvanic 
electricity,  from  the  well-known  substance,  lime.  It  is 
white,  solid,  inflammable  at  the  atmosphere,  and  decom- 
poses water  by  combining  with  its  oxygen,  setting  the  hy- 
drogen free.  It  combines  with  oxygen  in  two  proportions. 
The  most  remarkable  of  these  combinations, 

Protoxide  of  Calcium,  or  Lime, 

is  composed  of  1  equivalent  of  calcium  =  20 
I         do.         of  oxygen  =    8 


Consequently,  chemical  equivalent  of  lime  =  28. 

It  is  found  in  great  abundance,  combined  with  the  acids 
in  all  three  kingdoms  of  nature.  It  is  obtained  pure  by 
exposing  white  marble,  or  calcareous  spar  to  a  red  heat. 

§  159.  Properties  of  Lime.  It  is  a  soft,  white  mass, 
requiring  great  degrees  of  heat  for  its  fusion,  but  advan- 
cing remarkably  the  fusion  of  most  earthy  substances ; 
and  is  therefore  said  to  be  a  flux.  Its  taste  is  caustic  and 
astringent.  By  absorption  of  moisture  from  the  atmosphere, 
or  by  the  process  of  slaking  (mixing  it  with  water)  it 
becomes  converted  into  an  hydrate. 

The  use  of  Lime  is  very  general  and  diversified.  In  archi- 
tecture it  is  used  for  the  preparation  of  mortar  and  for  white- 
washing ;  in  chemistry  for  the  production  of  hydrate  of  pot- 
ash, soda,  and  ammonia ;  in  the  arts,  for  bleaching,  dyeing, 


J  88  BARIUM. 

and  tanning.  It  is  also  used  in  sugar-refineries,  and  in  the 
manufactory  of  glass  and  parchment.  Finally,  it  is  employed 
in  domestic  economy  to  absorb  the  moisture  from  fields. 

Calcium  combines  also  with  chlorine  to  chloride  of  cal- 
cium. When  this  substance  is  mixed  with  snow  its  refrig- 
erating power  is  so  great  as  to  freeze  mercury. 

The  chloride  of  lime,  which  is  a  combination  of  the  oxide 
of  calcium  with  chlorine,  will  be  described  in  the  4th  chapter 
among  the  salts. 

Recapitulation  of  the  principal  Combinations  of  Calcium. 

Calcium      ^  oxygen  to  lime  (Protoxide  of  Calcium). 
combines  with  £  ^^  to  ^  .^  ofcalcium^ 

5.     Barium. 

Chemical   Equivalent  =  70. 

§  160.  Barium  is  likewise  produced  by  galvanic  elec- 
tricity from  a  substance  called  carbonate  of  baryta.  It  is 
of  a  dark  grey  color,  has.  less  lustre  than  cast-iron,  is  soon 
oxidised  when  in  contact  with  the  atmosphere,  acts  vio- 
lently on  water  (which  is  decomposed  by  it),  and  burns 
when  heated  in  the  atmosphere,  with  a  dark  red  flame.  It 
combines  with  oxygen  in  two  different  proportions,  pro- 
ducing respectively  protoxide  and  peroxide  of  barium. 

The   protoxide  of  Barium  (Baryta),   also  called  Heavy 
Earth, 

is  composed  of  1  equivalent  of  barium  =  70 
1          do.        of  oxygen  =    8 


Chemical  equivalent  of  protoxide  of  barium  =  78. 

§  161.  Properties  of  Baryta.  It  is  a  greyish-white, 
earthy  substance,  which  does  not  melt  at  a  common  fire, 
has  a  burning,  caustic  taste,  and  is  very  poisonous.  When 
thrown  into  water  it  becomes  heated  and  deposites  a  white 
powder  (a  hydrate).  The  solution,  which  is  called  baryta 


STRONTIUM.  189 

water,   is  colorless,  possesses   all  the  alkaline  properties, 
and  upon  cooling  or  freezing  forms  regular  crystals. 

The  peroxide  of  barium  is  a  dirty-grey  mass,  suffering  great 
degrees  of  heat  without  being  decomposed. 

Barium  combines  also  with  chlorine,  sulphur,  and  iodine, 
forming  respectively  chloride,  sulphuret,  and  iodide  of 
Barium. 

Recapitulation  of  the  principal  Combinations  of  Barium. 


combines  with  \  chlorine  to  chloride  of  barium. 
v  sulphur  to  sulphuret  of  barium. 

6.     Strontium. 

Chemical  Equivalent  =  44. 

§  162.  Strontium  is  the  last  of  the  six  alkaline  metals, 
which,  like  the  rest,  has  been  obtained  by  galvanic  elec- 
tricity. It  has,  like  barium,  a  greyish  white  color,  and 
little  metallic  lustre.  It  combines  with  oxygen  in  two 
proportions,  forming  Protoxide  and  peroxide  of  Strontium. 

The  protoxide  of  Strontium,  —  Strontia,  (so  called 
from  the  town  of  Strontia,  in  Argyleshire,  where  the  na- 
tive carbonate  of  strontia  —  see  Chap.  IV  —  was  first 
discovered  in  1787)  is  generally  found  combined  with  sul- 
phuric and  carbonic  acid. 

It  is  composed  of  1  equivalent  of  strontium  =  44 
1          do.  of  oxygen  =    8 

Consequently,  chemical  equivalent  of  strontia  =  52. 

It  consists  of  a  greyish  white  powder,  which  does  not 
melt  at  a  common  fire  ;  has  a  sharp,  caustic  taste  (less 
than  baryta,  but  more  than  lime),  and  is  dissolved  in  boil- 
ing water  to  a  colorless  liquid,  called  strontia  water,  which 
possesses  all  the  alkaline  properties. 

Strontium  combines  yet  with  sulphur  and  chlorine  to 
sulphuret  and  chloride  of  strontium  respectively. 


190  MAGNESIUM. 

Recapitulation. 

I 

Strontium 
combines  with 


)  sulphur  to  sulphuret 
*  chlorine  to  chloride 


of  strontium. 


B.     OF  THE  six  EARTHY  METALS,  MAGNESIUM,  YTTRIUM, 

ALUMIUM,  GLUCINUM  (BERILLIUM),  ZIRCONIUM, 

AND   THORIUM. 

§  163.  The  existence  of  these  metals  is  not  so  much 
proved  by  actual  experiment  as  by  strong  reasoning  and 
analogy.  Their  oxides  were  formerly  known  by  the  name 
of  earths,  but  from  the  experiments  which  have  since  been 
made  upon  them,  and  the  strong  analogy  which  exists  be- 
tween them  and  the  oxides  of  the  alkaline  metals,  places 
their  metallic  origin  beyond  a  doubt  or  controversy.  It  is 
on  this  account  all  modern  chemists  have,  without  an  ex- 
ception, treated  of  these  substances  as  the  oxides  of  the 
metals  we  have  just  named,  although  they  cannot  be  con- 
verted to  the  metallic  state  by  any  ordinary  process  of 
reduction  (§  146,  page  179)  ;  nor  scarcely  by  any  process 
of  science  thus  far  known.  They  have  all  an  insipid 
taste,  different  from  the  fixed  alkalies,  which  taste  acrid  ; 
but  neutralize  the  acids  in  the  same  manner  as  other 
salifiable  bases. 

1.     Magnesium. 

Chemical  Equivalent  =  12,  (doubtful). 

§  164.  Magnesium  may  be  obtained  by  Voltaic  elec- 
tricity, or  by  the  action  of  potassium  on  a  substance  called 
chloride  of  magnesium. 

When  Voltaic  electricity  is  employed,  magnesium  in  con- 
tact with  mercury  is  exposed  for  a  long  time  to  the  action  of 
the  battery,  until  an  amalgam  is  formed,  which  upon  dry  dis- 
tillation (secluded  from  the  atmosphere),  during  which  the 
quicksilver  is  partly  converted  into  vapor,  yields  a  dark-grey, 


MAGNESIUM.  191 

metallic  film.  This  is  the  metal  magnesium.  By  the  second 
process,  chloride  of  magnesium,  a  substance  contained  in  sea 
and  well  water,  is  heated  in  a  platina  crucible  with  about  10 
parts  of  pure  potassium.  During  this  process  the  chlorine 
combines  by  elective  affinity  with  the  potassium,  setting  the 
magnesium  free. 

Magnesium  obtained  by  either  process  can  only  be  col- 
lected in  very  small  particles,  scarcely  sufficient  for  chem- 
ical investigation.  It  has  nevertheless  been  found  to  be  a 
white,1  ductile  substance,  of  great  metallic  lustre,  which  is 
infusible  in  close  vessels,  at  a  very  high  temperature,  but 
burns  when  heated  in  contact  with  atmospheric  air  with  a 
red  light,  and  with  scintillation.  It  combines  but  in  one 
proportion  with  oxygen,  the  product  being  the  oxide  of 
magnesium,  commonly  known  by  the  name  of 

Magnesia, 

whose  chemical  composition  is  supposed  to  be 

1  equivalent  of  magnesium  =  12 
1         do.  of  oxygen  =    8 


Consequently,  chemical  equivalent  of  magnesia  ==  20, 

although  the  exact  proportion  in  which  it  is  united  with 
oxygen  is  not  yet  ascertained. 

§  165.  The  oxide  of  magnesium  (Magnesia)  is  abun- 
dantly distributed  throughout  nature,  making  part  of  ex- 
tensive rock  formations,  and  being  also  largely  contained 
in  sea-water,  from  which  it  is  obtained  for  commerce.  In 
its  purest  state  it  is  best  obtained  by  submitting  carbonate 
of  magnesia,  a  substance  with  whose  properties  we  shall 
become  acquainted  in  the  4th  chapter,  (o  an  intense  red 
heat,  and  it  is  on  this  account,  by  apothecaries,  called  cal- 
cined magnesia  (because  the  process  of  calcination  con- 
sists in  burning  bodies  at  an  open  fire). 

Properties.  It  is  a  white,  soft  powder,  without  smell 
or  taste,  infusible  and  insoluble  in  water,  which  is  exten- 
sively used  in  medicine. 

Chloride  of  magnesium,  which  is  a  combination  of  magne- 
sium with  chlorine,  is  contained  in  sea  and  well  water,  and  it 


192  GLUCINUM. 

is  from  this  substance  that  pure  magnesia  may  be  obtained 
through  the  medium  of  potassium. 

Magnesium  combines  also  with  sodium  and  with  fluorine. 

Recapitulation. 

Magnesium    <  oxygen  to  oxide       \    e 
combines  with  \  chlorine  to  chloride  J  *•***«*• 

Glucinum    (Berillium). 

Chemical  Equivalent  =  20,  (doubtful). 

^  166.  Glucinum  is  produced  by  the  action  of  potassi- 
um on  a  peculiar  earth  called  Glucina  (berillious  earth). 

When  potassium  is  heated  with  this  earth  in  close  vessels, 
it  is  changed  into  potash,  and  dark-colored  globules  are  discov- 
ered disseminated  throughout  the  whole  mass,  which  are  the 
metal  Glucinum. 

To  this  inference  we  are  naturally  led  by  the  impossibility 
of  Potassium  being  converted  into  potash  without  absorbing 
oxygen  (potash  being  a  compound  of  potassium  and  oxygen), 
and  the  impossibility  of  its  absorbing  oxygen  from  any  other 
substance  than  from  the  earth  glucina,  since  it  is  this  sub- 
stance alone  with  which  it  is  brought  in  contact,  atmospher- 
ic air  being  excluded  by  the  experiment  being  performed  in 
close  vessels.  Thus  we  have  every  certainty  which  reasoning 
can  give,  that  glucina  is  a  combination  of  oxygen  with  some 
metal  which  is  its  basis.  This  reasoning  moreover  is  corrob- 
orated by  the  fact  that  metallic  globules  do  actually  appear 
disseminated  through  its  mass  when  the  experiment  above 
alluded  to  is  made  ;  and  to  all  this  is  yet  added  the  strong 
analogy  which  glucina  bears  to  those  substances  which  we 
know  to  be  oxides  of  metals,  and  which  are  reduced  to  the 
metallic  state  by  exactly  the  same  operation,  which  alone,  if  all 
experiments  failed,  would  be  sufficient  to  place  the  metallic 
base  of  glucina  almost  beyond  a  doubt. 

Properties.  It  is  a  dark-grey,  granular  powder,  which 
when  polished  assumes  a  metallic  lustre.  It  does  not  be- 
come oxydized  at  the  common  temperature  of  the  atmos- 
phere ;  but  burns  when  heated  with  great  splendor. 

Oxide  of  Glucinum,  Glucina,  Berillia,  is  known  only 
to  exist  in  a  few  rare  minerals.  It  is  a  white,  light  pow- 


YTTRIUM.  — ALUMIUM.  193 

der,  which  adheres  to  the  tongue  like  clay.     It  is  insolu- 
ble in  water,  but  is  readily  dissolved  in  liquid  potash  or 
soda.     Its  chemical  equivalent  is  supposed  to  be  28. 
Glucina  combines  also  with  sulphur  and  chlorine. 

3.      Yttrium. 

Chemical  Equivalent  =  34,  (doubtful). 

§  167.  This  substance  was  likewise  obtained  by  the  ac- 
tion of  potassium  on  a  substance  called  chloride  of  yttrium, 
in  the  same  manner  as  glucinum  is  obtained  from  glucina. 

Properties.  It  consists  of  grey,  metallic  scales,  which, 
when  polished,  assume  a  dark  lustre.  It  does  not  combine 
with  oxygen  at  low  temperatures,  but  when  heated  burns 
with  a  dazzling  light. 

Oxide  of  yttrium  is  found  in  a  mineral  (ytterby)  and 
in  several  other  fossils  in  Sweden.  It  is  a  yellowish  white 
powder,  inodorous,  tasteless,  insoluble  in  water,  and  infu- 
sible at  a  common  red  heat.  It  combines  with  most  of 
the  acids,  forming  a  class  of  salts  which  are  all  more  or  less 
distinguished  by  a  sweetish  taste,  like  sugar.  Its  chem- 
ical equivalent  is  supposed  to  be  42. 

4.     Alumium. 

Chemical  Equivalent  =  10,  (doubtful). 

§  168.  This  is  another  mineral,  which  has  been  pro- 
duced by  the  action  of  potassium  on  chloride  of  alumium. 
It  is  a  grey,  granular  powder,  with  a  metallic  lustre  like 
that  of  tin  ;  when  strongly  heated  it  burns  in  contact  with 
atmospheric  air,  the  residue  being  a  white  clay  which 
scratches  glass. 

Oxide  of  Alumium  —  Alumia. 

This   compound   of  alumium  with    oxygen,  is  probably 
composed  of  1  equivalent  of  alumium  =  10 
1         do.  of  oxygen  =   8 

Chemical  equivalent  of  alumia=  18. 
17 


194  ZIRCONIUM, 

§  169.  Properties  of  Alumia.  It  is  an  abundant  pro- 
duct of  nature,  occurring  either  in  its  simple  form,  or  as 
a  hydrate,  or  combined  with  the  acids  and  earths  as  a 
constituent  part  of  rocks  and  alluvial  depositions. 

In  its  pure  state  it  is  contained  in  some  of  the  gems,  viz. : 
In  sapphire  (blue) ;  in  the  red  oriental  ruby,  in  topaz  (yel- 
low), amethyst  (violet),  in  the  emerald  (green).  The  dif- 
ferent kinds  of  clay  used  in  the  manufacture  of  glass  and 
porcelain  contain  hydrate  of  alumia  in  a  greater  or  less 
proportion.  It  is  a  loose,  white  powder,  without  taste  or 
smell,  infusible  at  a  common  red  heat,  and  insoluble  in 
water ;  but  has  nevertheless  a  strong  attraction  for  moisture. 
It  combines  permanently  with  some  dyeing  stuffs,  where- 
fore it  is  used  in  calico  printing. 

.Alumium  combines  yet  with  chlorine  to  chloride  of 
alumium,  with  sulphur  to  sulphuret,  and  with  fluorine  to 
fluoride  of  alumium.  Neither  of  these  compounds  is  of 
much  application  in  the  arts. 

Recapitulation. 

C  oxygen  to  alumia. 

Jllumium  combines  with  <  chlorine  to  chloride  of  alumium. 
(  sulphur  to  sulphuret  of  alumium. 

5.     Zirconium. 

Chemical  Equivalent  not  ascertained. 

§  170.  This  metal  has  been  obtained  (by  Berzelius) 
by  heating  potassium  with  a  salt  called  fluate  of  zirconia. 
It  is  a  black,  dry  powder,  of  a  dark,  metallic  lustre, 
which  burns  at  a  heat  a  little  before  redness,  and  is  a  bad 
conductor  of  electricity. 

Oxide  of  Zirconium,  zirconia,  has  been  found  only  in  a 
few  minerals,  the  zircon  (a  precious  stone)  of  Ceylon,  and 
the  hyacinth  from  France.  It  is  a  fine,  white  powder, 
without  smell  or  taste,  scratches  glass,  and  is  insoluble  in 
water. 


THORIUM. -MERCURY.  195 


6.       Thorium. 

§  171.  This  metal  was  produced  by  the  action  of  heat- 
ed potassium  on  a  substance  called  chloride  of  thorium,  as 
glucinum  is  produced  from  glucina.  It  is  a  grey,  heavy 
powder, which  by  pressure  assumes  a  metallic  lustre,  does 
not  become  oxidized  in  water,  but  burns  when  exposed  to 
a  moderate  heat  with  great  splendor.  The  product  of  the 
combustion, 

Oxide  of  Thorium,  or  Thoria,  which  is  also  found  in  na- 
ture, is  a  Norwegian  fossil,  called  thoria,  whence  its  name. 


C.       OF    THE      NINE    NOBLE     METALS,     MERCURY,     SlLVER, 

GOLD,  PLATINUM,    PALLADIUM,    RHODIUM, 
IRIDIUM,  OSMIUM,  AND  NICKEL. 

1.      Mercury. 

Chemical  Equivalent  ?=  200. 

§  172.  This  metal  occurs  comparatively  but  sparingly 
in  the  mineral  kingdom.  But  few  countries  possess  quick- 
silver mines.  It  is  found  either  native  (as  virgin  quick- 
silver) ,  or  combined  in  sulphur  or  mercurial  ore. 

This  ore  is  reduced  by  heating  it  with  iron  filings  or  lime. 
During  the  process  the  sulphur  combines  by  elective  affinity 
with  the  iron  or  lime,  setting  the  mercury  free,  which,  by  the 
heat  is  volatilized,  and  passes  over  into  a  receiver,  where  in 
contact  with  the  colder  sides  of  the  vessel  it  is  again  condensed 
into  the. liquid  form. 

§  173.  Properties.  It  is  the  only  metal  which  is 
liquid  at  the  common  temperature  of  the  atmosphere.  It 
is  perfectly  tasteless,  has  a  bluish  white  color  and  a  strong 
metallic  taste.  It  freezes  at  40°  below  zero  of  Fahren- 
heit, and  boils  at  660°  of  the  same  scale.  When  congealed 
it  is  malleable,  and  may  be  cut  with  a  knife  or  hammered 
into  thin  plates.  It  is  so  extremely  volatile  that  its  vapors 
rise  even  at  low  temperatures,  especially  in  a  vacuum.  On 


196  MERCURY. 

this  account  all  the  thermometers  and  barometers  (Nat- 
ural Phil.  Chaps.  V  and  VI),  are  more  or  less  incorrect  by 
the  pressure  of  the  vapors  of  mercury  which  rise  in  the 
vacuum  above  it. 

§  174.  Mercury  has  the  power  of  uniting  to  amalgams 
with  most  metals,  but  more  especially  with  gold,  tin,  silver, 
zinc,  lead,  and  bismuth,  which  it  dissolves  in  minute 
quantities. 

This  affords  a  means  of  extracting  gold  from  other  sub- 
stances with  which  it  is  mixed  in  small  quantities.  Thus, 
gold  beaters  are  in  the  habit  of  shaking  their  dust  with  mercu- 
ry, which  amalgamate  with  the  gold,  from  which  the  gold  may 
afterwards  be  obtained  by  heat,  the  quicksilver  being  volatil- 
ized, while  the  gold  remains  in  the  solid  state  (compare  §  142, 
page  177).  Or  it  is  also  customary  to  press  the  amalgam  thus 
formed  through  a  buckskin  bag,  which  allows  the  mercury  to 
go  through,  but  retains  the  gold. 

Another  application  of  the  amalgam  of  gold  is  made  in  the 
process  of  water  gilding,  which  is  performed  by  means  of  this 
amalgam.  An  amalgam  of  quicksilver  with  silver  is  employed 
in  the  same  way  to  imitate  plated  ware. 

The  amalgam  of  tin  is  largely  employed  in  silvering  the 
backs  of  looking  glasses.  For  this  purpose  the  quicksilver  is 
simply  poured  upon  a  sheet  of  tin  foil,  and  the  plate  afterwards 
pressed  upon  it,  care  being  taken  to  place  the  plate  upon  the 
amalgam  in  such  a  way  as  not  to  allow  any  air  to  remain  be- 
tween it  and  the  metal.  The  plate  remaining  in  this  manner 
pressed  upon  the  amalgam,  for  a  time  not  exceeding  48  hours, 
the  process  in  completed,  and  the  amalgam  adheres  afterwards 
to  the  plate  merely  by  the  adhesive  attraction  which  exists 
between  these  substances.  The  amalgam  of  tin  and  mercury 
is  also  used  for  electrical  machines,  Leyden  phials,  and  a  num- 
ber of  processQs  in  the  arts. 

Combinations  of  Mercury  with   Oxygen. 

§  175.  Mercury  combines  with  oxygen  in  two  differ- 
ent proportions,  producing  respectively  protoxide  and  per- 
oxide of  mercury. 


MERCURY.  197 


Protoxide  of  Mercury 

is  composed  of  1  equivalent  of  mercury  =  200 
1         do.         of  oxygen  =      8 


Consequently,  chem.  equiv.  of  prot.  of  mercury  =  208. 

It  is  obtained  when  quicksilver  is  violently  agitated  in 
contact  with  atmospheric  air.  By  this  means  the  quick- 
silver is  converted  into  a  greyish  black  powder,  which  is 
insipid  and  insoluble  in  water,  and  combines  with  a  greater 
portion  of  oxygen  when  gently  heated  in  contact  with  at- 
mospheric air.  The  compound  then  formed  is 

Peroxide  of  Mercury  t 

which  is  composed  of  1  equivalent  of  mercury  =  200 
and  2  equivalents  of  oxygen  (each  =  8)  =    16 


Consequently,  chem.  equiv.  of  peroxide  of  mercury  =216. 

§  176.  This  compound,  as  we  see  from  its  chemical 
composition,  is  composed  of  mercury  combined  with  a 
double  quantity  of  oxygen,  and  is  most  readily  obtained  by 
dissolving  mercury  in  nitric  acid  and  applying  afterwards 
a  sufficient  degree  of  heat  to  the  solution  to  expel  the  acid. 

Properties.  It  is  of  a  dark  red  color,  and  but  sparingly 
soluble  in  water,  to  which  it  communicates  the  property  of 
turning  blue  vegetable  colors  into  green.  When  distilled 
in  a  glass  tube  it  parts  again  with  its  oxygen  and  the  met- 
al is  revived. 

Both  oxides  of  mercury  combine  with  the  acids  to  salts, 
wherefore  they  are  called  salifiable  bases  (see  Introduction 
page  38). 

Combinations  of  Mercury  with  Chlorine. 

§  177.  Mercury  combines  also  in  two  proportions  with 
chlorine,  forming  Proto-chloride  and  Perchloride  of  Mer- 
cury. 

17* 


198  MERCURY. 


Proto-Chloridc  of  Mercury  —  (  Calomel)  t 

is  composed  of  1  equivalent  of  mercury  =  200 
and  1          do.       of  chlorine  =    36 


Consequently,  chemical  equivalent  of  proto-chlo- 

ride  of  mercury  =  236. 

§  178.  This  compound  is  obtained  directly  by  bringing 
the  mercury  in  contact  with  chlorine,  at  the  common  tem- 
perature of  the  atmosphere.  It  is  also  formed  when  a  solu- 
tion of  common  salt  is  poured  upon  a  solution  of  mercury  in 
nitric  acid.  The  chlorine  of  which  common  salt  is  composed 
(which  is  a  chloride  of  sodium)  combines  then  with  the 
mercury  to  a  heavy,  white  powder  which  is  precipitated ; 
and  must  afterwards  be  washed  and  dried  at  a  gentle  heat. 
The  compound  thus  obtained  forms  that  celebrated  medi- 
cine, known  by  the  name  of  calomel,  which  is  now  of  al- 
most universal  application,  but  was  first  employed  and 
prepared  by  Dr  Bahneman,  late  Professor  of  Medicine  in 
Leipzig. 

Per-Chloride  of  Mercury  —  (Corrosive  Sublimate) 

consists  of  1  equivalent  of  mercury  =  200 
2  equivalents  of  chlorine  (each  =  36)  =    72 


Consequently,  chemical  equivalent  of  per-chlo- 

ride  of  mercury  =  272. 

§  1T9.  This  substance  affords  a  powerful  illustration  of 
the  power  of  heat  to  increase  chemical  affinity  (see  Intro, 
page  5).  We  have  said  in  the  last  section  that  proto- 
chloride  of  mercury  is  obtained  by  bringing  chlorine  and 
mercury  in  contact  at  the  common  temperature  of  the  at- 
mosphere, but  if  this  be  done  when  mercury  is  heated,  its 
affinity  for  chlorine  increases,  in  which  case  it  combines 
with  a  double  proportion  of  chlorine,  forming  the  com- 
pound whose  chemical  composition  we  have  stated  at  the 
head  of  this  section.  Corrosive  Sublimate  is  also  prepar- 
ed for  medicinal  purposes  by  subliming  a  mixture  of  73 
parts  of  a  salt  known  by  the  name  of  sulphate  of  mercury 
with  120  parts  of  common  table  salt  (a  chloride  of  sodium). 


MERCURY.  199 

(The  sulphate  of  mercury,  which  is  a  compound  of  sul- 
phuric acid  with  mercury,  is  obtained  by  boiling  to  dry- 
ness  50  parts,  by  weight,  of  mercury,  and  70  of  sulphuric 
acid). 

§  180.  Properties.  Corrosive  sublimate  thus  obtain- 
ed has  a  crystalline  texture,  is  perfectly  colorless,  soluble 
in  water,  and  has  a  hot,  acrid  taste.  When  taken  in  its 
pure  state  it  is  highly  poisonous.  One  of  the  most  distress- 
ing symptoms  accompanying  the  poisoning  by  corrosive 
sublimate  is  the  swelling  of  the  glands  and  throat,  which, 
if  it  be  taken  in  large  quantities,  terminates  in  suffocation. 
It  is  nevertheless  much  used  in  medicine. 

Combinations  of  Mercury  with  Sulphur. 

§  181.     Mercury  unites  yet  with  sulphur  in  two  differ- 
ent proportions,  forming  respectively  proto-sulpJiuret  and 
bi-sulphuret  of  mercury.     The  first  of  these  combinations 
may  be  obtained  by  triturating  together  mercury  and  sul- 
phur, or  by   passing  a  current   of  sulphuretted  hydrogen 
through  water   in  which  powdered  chlorine  is  suspended. 
It  is  composed  of  1  equivalent  of  mercury  =  200 
1          do.         of  sulphur  =    16 

Its  chemical  equivalent  therefore,  is  =  216. 
Bi-sulphuretted  Mercury 

is  composed  of  1  equivalent  of  mercury  =  200 
and  2  equivalents  of  sulphur  (each  =  16)  =    32 


Consequently,  chemical  equivalent  of  bi-sulphu- 

ret  of  mercury  :=  232. 

182.  This  compound,  also  known  by  the  name  cin- 
er,  is,  as  we  have  had  occasion  to  say  before,  the  prin- 
cipal ore  from  which  mercury  itself  is  obtained  ;  but  it 
may  also  be  produced  by  art,  by  fusing  together  mercury 
and  sulphur,  and  subliming  the  compound.  It  is  af  a 
beautiful  red  color,  and  is  employed  as  a  red  pigment, 
known  by  the  name  of  vermilion. 


200  SILVER. 

Recapitulation  of  the  principal  Binary  Combinations  of 
Mercury. 

(  oxygen  to 


ith<( 


combines  with  "Worine  to 


f  sulph 


ur  to 


2. 


per-oxide 


proto-sulphuret 
per-sulphuret 


Chemical  Equivalent  =  110. 

§  183.  This  well-known  metal  is  found  native,  or  mix- 
ed with  chlorine,  sulphur,  copper,  and  other  metals,  in  a 
great  many  countries,  but  particularly  in  South  America 
and  Mexico.  It  is  of  a  beautiful  white  color  and  great 
lustre,  which  is  only  surpassed  by  polished  steel.  It  is  very 
malleable  and  possesses  very  great  ductibility.  It  maybe 
hammered  into  leaves  of  not  more  than  one  ten  thousandth 
part  of  an  inch  in  thickness,  and  drawn  out  into  wire  of 
the  breadth  of  a  hair.  It  is  seldom  (even  by  art)  obtain- 
ed in  an  entirely  pure  state,  being  generally  alloyed  with 
a  small  portion  of  copper.  Most  silver  contains  also  a 
small  quantity  of  gold  (about  ^  per  cent),  which  for  the 
want  of  a  cheap  method  of  refining  it,  has  until  of  late, 
been  suffered  to  remain  with  it*.  The  uses  of  silver  for 
coins,  ornaments,  instruments,  vessels,  &c,  are  sufficiently 
known.  It  is  eminently  calculated  for  all  these  purposes, 
on  account  of  its  unalterability,  being  only  tarnished  by 
vapors  of  sulphur,  and  resisting  oxidation  even  when  ex- 
posed to  moisture  in  contact  with  heat. 

Combinations  of  Silver. 

§  184.  Silver  by  uniting  with  oxygen,  chlorine  and 
sulphur,  forms  the  three  respective  compounds,  oxide,  chlo- 
ride, and  sulphuret  of  silver.  The  first  of  these  combi- 
nations, '  '''*£- 

*  It  has  lately  been  extricated  from  the  silver  of  some  of  the  mines 
in  Saxony. 


SILVER.  201 


Oxide  of  Silver , 

is  composed  of  1  equivalent  of  silver  =  110 
and  I         do.     of  oxygen  =      8 


Its  chemical  equivalent,  therefore,  is  =  118 

It  is  obtained  by  adding  lime-water  to  a  solution  of  sil- 
ver in  nitric  acid.  It  possesses  an  olive  color,  is  insoluble 
in  water,  and  perfectly  tasteless. 

Chloride  of  Silver 

is  composed  of  1  equivalent  of  silver  =  110 
1        do.     of  chlorine  =    36 


Consequently,  chem.  equiv.  of  chloride  of  silver  =  146. 

It  is  commonly  known  by  the  name  of  horn  silver,  and 
obtained  by  adding  a  solution  of  common  salt  to  one  of 
silver  in  nitric  acid.  The  precipitate  thus  formed  is  the 
chloride  of  silver,  which  at  first  is  white,  but  gradually 
becomes  dark,  and  finally  black,  when  exposed  to  the 
rays  of  the  sun.  It  is  insoluble  in  water,  and  when  heated 
in  a  silver  crucible,  forms  upon  cooling,  semi-transparent 
crystals,  similar  to  horn  (hence  the  name  of  horn  silver). 

A  mixture  of  chloride  of  silver,  chalk  and  pearl-ash  is  used 
for  silvering  brass.  The  brass  must  for  this  purpose  be 
well  cleaned,  and  the  mixture,  a  little  moistened  with  water, 
rubbed  upon  its  surface. 

Sulphurct  of  Silver 

is  composed  of  1  equivalent  of  silver  =  110 
1          do.     of  sulphur  =    16 


Consequently,  chem.  equiv.  of  sulphuret  of  silver  =  126. 

This  compound  occurs  in  silver  mines,  but  may  also  be 
produced  by  art  by  placing  thin  plates  of  silver  and  sul- 
phur upon  one  another,  and  heating  them  gently  at  a  low 
red  heat.  As  this  compound  is  much  more  fusible  than 
pure  silver,  the  pure  metal  may  be  extricated  from  it  by 
heat.  Another  way  of  producing  it  is  by  passing  sulphu- 
retted hydrogen  through  a  solution  of  silver  in  nitric  acid. 


202  GOLD. 

It  is  of  a  black  color,  but  when  fused  is  employed  in  the 
manufactory  of  silver  ornaments. 

Recapitulation    of  the  principal  combinations  of  Silver. 

C  oxygen  to  oxide  of  silver. 

Silver  combines  with  1  chlorine  to  chloride  of  silver, 
(sulphur  to  sulphuret  of  silver. 

3.      Gold. 

Chemical  Equivalent  —  200. 

§  185.  Gold  belongs  to  those  metals  which  on  account 
of  their  being  found  in  a  native  state,  were  known  to  the 
remotest  people  of  antiquity.  It  occurs  either  in  its  sim- 
ple form,  or  combined  with  silver,  tellurium,  rhodium, 
&c.  Native  gold  is  found  in  various  shapes  in  Europe, 
Asia,  Jlfrica,  and  America,  in  Ceylon,  Sumatra,  Java, 
Borneo  and  the  Philippine  Islands. 

Properties.  It  is  of  a  beautiful  yellow  color,  and  about 
19  times  heavier  than  water  (its  specific  gravity  being  19, 
that  of  water  taken  for  1).  Hammered  out  into  thin 
leaves  it  transmits  the  rays  of  the  sun,  the  light  passing 
through  it  appearing  green.  It  is  more  malleable  and 
ductile  than  any  of  the  metals  ;  T\y  of  a  grain  of  it  may  be 
hammered  out  to  cover  37  square  feet  of  surface.  Ac- 
cording to  Reaumure,  a  French  philosopher,  one  grain  of 
gold  may  be  drawn  into  a  piece  of  wire  500  Paris  feet 
long,  and  38  grains  of  the  same  metal  are  sufficient  to 
cover  a  piece  of  silver  wire  upwards  of  one  thousand  miles 
in  length!  !  It  is  perfectly  unchangable  byjire,  moisture, 
or  air,  and  is  only  acted  upon  by  one  solvent,  which  is  a 
mixture  of  muriatic  and  nitric  acid  (neither  of  these  acids 
does  alone  affect  gold),  which  from  this  property  of  dis- 
solving gold  has  been  called  aqua  regia  (king's  water) ; 
because  the  alchymists  considered  gold  as  the  king  of 
metals. 

Gold  is  used  like  silver  for  coins  and  ornaments,  and 
possesses  the  greatest  value  of  any  metal  known. 


GOLD.  203 

Gold  from  a  state  of  solution  may  easily  be  revived  by  any 
substance  which  has  a  strong  affinity  for  oxygen,  for  which 
gold  has  but  a  feebly  affinity.  Hence  if  a  ribbon  or  some  other 
substance  be  moistened  with  a  dilute  solution  of  gold  in  aqua 
regia,  and  afterwards  exposed  to  a  current  of  hydrogen,  the 
gold  will  be  revived  and  cover  the  stuff.  When  the  solution 
is  applied  in  regular  figures,  by  means  of  a  camel's-hair  pen- 
cil, it  will  afford  a  beautiful  experiment,  particularly  to  young 
scholars.  An  etherial  solution  of  gold,  which  is  formed  by 
pouring  sulphurous  ether  into  a  solution  of  gold,  is  employed 
for  gilding  steel  instruments,  to  preserve  them  from  rust  or 
moisture.  The  solution  is  easily  prepared  by  adding  2  ounces 
of  ether  to  one  ounce  of  the  solution  of  gold  ;  when  the  vessel 
is  thoroughly  shaken  and  afterwards  allowed  to  stand  for  a  few 
minutes,  the  ether  which  does  not  mix  with  the  acid,  and 
which,  on  account  of  its  being  specifically  lighter,  will  float  on 
top,  may  be  poured  off  into  another  vessel.  Any  steel  instru- 
ment dipped  into  the  etherial  solution  will  instantly  receive  a 
thin  coating  of  gold. 

Combinations  of  Gold. 

§  186.  Gold  combines  in  two  different  proportions 
with  oxygen.  The  products  are  protoxide  of  gold,  and 
deutoxide  of  gold,  or  auric  gold.  Neither  of  these  combi- 
nations is  used  in  the  arts,  neither  is  their  nature  and 
composition  precisely  known  or  understood.  The  same 
holds  of  the  combinations  of  gold  with  chlorine  (see  Chlo- 
ride of  Gold,  Chap.  IV).  Sulphuret  of  gold  is  obtained 
like  that  of  silver  (see  §  184,  page  201),  by  passing  sul- 
phuretted hydrogen  through  a  solution  of  the  metal. 

The  principal  combinations  of  gold  may  therefore  be 
arranged  as  in  the  following  table  : 


Gold  combines   ""»  J  cMorine  to  chloride  of  gold. 
v.  sulphur  to  sulphuret  of  gold. 


204  PLATINUM. 


4.     Platinum. 

Chemical  Equivalent  =  96. 

§  187.  The  Spanish  philosopher,  Antonio  d'Ulod,  ob- 
served the  ore  of  platinum,  in  1736.  An  Englishman  by 
the  name  of  Wood  brought  it  first  to  Europe,  where  it 
was  analyzed,  and  found  to  contain  besides,  four  different 
metals,  viz.  Palladium,  Rhodium,  Iridium,  and  Osmium. 
It  has  since  been  found  in  Russia,  where  it  is  used  for 
coin,  for  which  it  is  admirably  adapted  on  account  of  its 
hardness  and  unalterability. 

Properties.  It  is  of  a  white  color,  somewhat  resem- 
bling steel,  but  has  less  lustre  than  silver.  Like  gold  it  is 
not  acted  upon  either  by  a  common  fire,  moisture  or  air ; 
nor  by  any  of  the  acids  alone,  but  is  likewise  dissolved 
by  a  mixture  of  nitric  and  muriatic  acid.  When  very 
pure  it  is  soft,  ductile,  and  may  be  hammered  out  into 
leaves,  but  cannot  be  drawn  into  suclnjine  wire  as  either 
gold  or  silver.  It  is  a  good  conductor  of  heat  and  electri- 
city, exceedingly  difficult  of  fusion,  and  the  heaviest  of  all 
substances  known  (its  specific  gravity  being  21 .5,  that  of 
water  taken  for  1). 

Besides  the  coining  of  money  it  is  yet  used  for  a  variety 
of  scientific,  particularly  chemical  purposes.  It  unites 
with  oxygen,  chlorine  and  sulphur  ;  but  the  nature  of  these 
combinations  is  not  precisely  ascertained. 

Among  the  various  applications  of  platinum  in  chemistry, 
we  will  only  mention  a  few,  which  will  sufficiently  serve  for 
an  illustration. 

1st.  It  is  used  for  crucibles  in  all  such  cases  where,  in  the 
course  of  a  chemical  process  some  acid  is  to  be  employed  which 
would  corrode  or  act  upon  some  other  metal,  or  which  would 
operate  upon  glass. 

2d.  It  is  used  in  the  manufacture  of  a  number  of  chemical 
and  physical  apparatus,  particularly  in  electric  and  galvanic 
batteries,  where  it  is  used  as  a  conducting  wire. 


PLATINUM. 


205 


Fig.  CXI II. 


3d.  In  the  construction  of  the  flameless  or  aphlogistic  lamp, 
which  is  represented  in  the 
adjoining  figure.  It  consists 
principally  of  a  glass  tube  seve- 
ral inches  long,  which  must  be 
fitted  to  a  small  bottle  or  some 
other  low  vessel  (as  represented 
in  the  figure)  by  means  of  a 
wooden  cork,  which  has,  besides, 
another  aperture  C,  for  the  pur- 
pose of  feeding  the  lamp  with 
alcohol.  Into  the  glass  tube  is 
inserted  a  coil  of  platina  wire, 
wound  round  a  piece  of  wood, 
which  is  shaped  somewhat  con- 
ical (tapering),  with  its  lower 
end  turned  upwards.  A  piece  of 
wick  establishes  a  communica- 
tion between  the  alcohol  and 
the  platina  wire. 

When  the  lamp  is  to  be  used  the  platina  may  be  ignited 
by  the  flame  of  a  candle,  which  being  afterwards  blown  out, 
the  wire  will  still  remain  red  hot,  and  emit  a  feeble  light,  as 
long  as  there  is  any  alcohol  remaining  in  the  vessel. 

This  phenomenon  is  explained  in  the  following  way.  When 
the  wire  is  ignited,  its  temperature  is  sufficiently  raised  to  in- 
flame the  alcohol,  which  as  we  well  know,  is  a  highly  combus- 
tible substance ;  but  this  being  once  done,  the  heat  given  out 
by  the  burning  alcohol  is  sufficient  to  keep  the  platina  wire 
red  hot,  even  after  its  flarne  is  blown  out. 

Another  application  of  platinum  is  made  in  the  preparation 
of  platinum-sponge,  for  the  purpose  of  producing  instantaneous 
light.  Platinum-sponge  is  a  substance  which  is  obtained  by 
dissolving  platinum  in  a  mixture  of  nitric  and  muriatic  acid, 
and  precipitating  the  metal  from  this  solution  by  the  addition 
of  some  muriate  of  ammonia.  This  precipitate  being  after- 
wards exposed  in  a  crucible  to  a  red  heat,  the  acid  and  ammo- 
nia are  evaporated  and  the  metal  remains  in  a  spongy  mass, 
which  on  that  account  has  been  called  platinum-sponge.  Its 
most  remarkable  property  consists  in  the  manner  in  which  it  is 
aifected  by  hydrogen  gas,  and  which  is  not  yet  sufficiently  ex- 
plained. A  jet  of  this  gas  being  directed  upon  it,  in  contact 
with,  and  at  the  common  temperature  of  the  atmosphere,  the 
platinum-sponge  becomes  immediately  red  hot,  and  ignites  the 
hydrogen. 

18 


206 


PALLADIUM. 


Fig.    CXIV. 


Upon  this  property  of 
platinum-sponge,  Professor 
Dobereiner  of  the  Univer- 
sity of  Jena,  founded  the 
following  simple  apparatus 
for  obtaining  instantaneous 
light.  Two  glass  vessels, 
A  and  B,  (see  the  figure) 
are  fitted  to  each  other  as 
represented  in  the  figure, 
the  vessel  A,  having  a 
tubular  prolongation  which 
is  ground  air-tight  into  the 
mouth  of  the  vessel  B.  This 
prolongation,  which  reaches 
nearly  to  the  bottom  of  the 
vessel  B,  being  surrounded 
by  small  strips  of  zinc,  and 
sulphuric  acid  being  poured  into  B,  hydrogen  gas  will  be  evol- 
ved, as  in  the  experiment  represented  in  Fig.  LXX  VIII,  page 
65,  which  by  its  pressure  will  force  part  of  the  liquid  through  the 
tube  into  the  upper  vessel  A.  The  remainder  of  the  gas  being 
compressed  by  the  weight  of  the  water  and  the  acid,  a  portion  of 
it  will  rush  forth  in  a  jet  from  the  mouth  of  the  pipe  P,  when  the 
stop-cock  C,  is  turned  open.  This  jet  being  directed  upon  some 
grains  of  platinum-sponge,  the  latter  will  instantly  become  red 
hot  and  ignite  the  hydrogen,  which  in  its  turn  sets  fire  to  the 
wick  of  a  small  candle,  which  must  be  placed  between  the 
mouth  of  the  pipe  and  the  platinum-sponge. 

Besides  the  applications  we  have  mentioned,  platinum  ad- 
mits of  many  others,  in  Chemistry  and  Natural  Philosophy,  to 
which  the  unalterability  and  ductability  of  the  metal  seem  to 
be  particularly  adapted ;  and  there  can  be  no  doubt  but  that  its 
uses  would  become  as  frequent  as  those  of  iron,  if  it  were 
found  in  larger  quantities,  and  reduced  from  its  ores  by  a  more 
simple  process  than  is  known  in  the  present  state  of  the  sci- 
ence. 


5.     Palladium. 

Chemical  Equivalent  =  56. 

§  188.     Palladium,  as    we  have  observed  in  the  last 
section,  is  contained  in  raw  platinum  ore.     It  is  also  found 


RH  O  D  I  U  M  .  —  I  RI  D I  U  M  .  —  OS  M I  U  M.  207 

combined  with  gold  in  Brazil.  Its  color  is  similar  to  that 
of  platinum.  It  is  ductile  and  may  be  rolled  into  leaves, 
or  drawn  into  wire:  It  is  less  fusible  than  gold,  tarnishes 
when  heated,  but  assumes  again  its  original  lustre  when 
submitted  to  higher  degrees  of  temperature.  It  is  acted 
upon  (dissolved)  by  the  nitric,  sulphuric,  and  muriatic 
acids.  It  combines  with  oxygen  and  sulphur.  The  pro- 
duct of  the  last  combination,  sulphuret  of  palladium,  is  of 
a  greyish  white  color,  has  a  metallic  lustre,  and  is  brittle 
and  easily  fusible. 

(5.     Rhodium. 

Chemical  Equivalent,  (not  ascertained). 

§  189.  This  metal  (likewise  contained  in  platinum) 
has  but  lately  been  found  combined  with  gold.  It  is  white 
(like  silver),  hard,  brittle,  and  infusible  at  a  common  red 
heat.  It  is  not  acted  upon  by  any  acid,  except  when  al- 
loyed with  another  metal,  but  becomes  oxydized  when 
calcined  with  potassium. 

The  oxide  thus  obtained  is  a  hydrate  of  a  brown  color,  and 
astringent  taste,  which  is  dissolved  by  most  acids,  and  com- 
bines with  the  alkalies  and  earths  in  several  proportions. 

7.  Iridium. 

Chemical  Equivalent  (not  ascertained). 

§  190.  Iridium  is  found  united  with  osmium  (see  next 
section)  in  form  of  small,  black  globules,  from  which  it  is 
afterwards  separated  by  the  action  of  muriatic  acid.  It  is 
a  white,  heavy  metal,  which  is  not  acted  upon  by  any  acid, 
and  is  fusible  only  in  small  quantities  by  the  agency  of 
powerful  galvanic  batteries. 

8.  Osmium. 

Chemical  Equivalent  (not  ascertained). 
§  191.     This  metal  is  obtained  by  the  same  process  as 


208  NICKEL.— IRON 

iridium.  It  is  a  greyish,  black,  or  blue  powder,  which  is 
acted  upon  by  nitric  acid;  small  quantities  of  it  burn 
when  transmitted  to  a  red  heat  in  contact  with  the  atmos- 
phere. The  acid  which  is  formed  by  the  combustion  of 
the  metal  is  soluble  in  water,  and  emits  a  peculiar  odor 
(from  which  the  metal  derived  its  name.*) 

9.     Nickel 

Chemical  Equivalent  =  30. 

§  192.  Nickel  is  not  an  abundant  product  of  nature, 
and  is  generally  united  with  cobalt  or  arsenic  (the  latter 
combination  is  known  in  Commerce  by  the  name  ofspliss). 
It  has  almost  a  silver-white  color,  a  strong  metallic  lustre, 
is  not  easily  fusible,  but  ductile  (when  cold  or  warm),  and 
may  be  drawn  into  wire  or  rolled  and  hammered  into  plates. 
It  does  not  become  oxydized  in  contact  with  the  atmosphere 
at  common  temperatures,  but  burns  in  pure  oxygen.  It  is 
attracted  by  the  magnet,  and  is  itself  capable  of  receiving 
and  exhibiting  magnetic  power,  in  a  degree  less  than  iron 
but  greater  than  cobalt  (see  Nat.  Phil.  Chap.  X).  When 
heated  in  contact  with  atmospheric  air  it  is  converted  into 
a  dark  powder>  oxide  of  Nickel,  which  is  yet  possessed  of 
magnetic  properties. 


D.       OF     THE     REMAINING      METALS,     IRON,    TlN,      LEAD, 

COPPER,  ZINC,  BISMUTH,  COBALT,  ANTIMONY,  AR- 
SENIC,   MANGANESE,    TELLURIUM,    TITANIUM, 
CERIUM,  URANIUM,  COLUMBIUM,  TUNGSTEN, 
CADMIUM,  CHROMIUM,  MOLYBDENUM, 
AND    VANADIUM. 

1.     Iron. 

Chemical  Equivalent  =  28. 

§   193.     No  metal  is  of  such  importance  to  mankind  as 
*  From  a  Greek  word,  signifying  odor. 


IRON.  209 

iron ;  it  is  almost  indispensable  to  civilization.  Neither 
gold  nor  silver  are  so  intimately  connected  with  the  power 
and  prosperity  of  a  people.  By  a  wise  distribution  of  Prov- 
idence, it  is  most  abundantly  diffused  throughout  the  whole 
globe,  and  is  found  in  all  three  kingdoms  of  nature.  It  is 
generally  met  with  in  an  oxydized  state,  native  only  in  me- 
teor stones*  and  in  some  of  the  fossils.  It  is  of  a  bluish- 
grey,  sometimes  white  color,  and  susceptible  of  the  high- 
est polish.  It  is  malleable  and  ductile,  and  may  be  drawn 
into  wire  ;  but  cannot  be  beaten  into  very  thin  leaves,  like 
gold  or  silver.  It  is  very  hard  and  infusible ;  but  when 
red  hot  it  is  soft  and  capable  of  receiving  any  form,  by 
hammering.  It  is  strongly  attracted  by  the  magnet,  and 
is  itself  capable  of  receiving  all  magnetic  virtues. 

The  native  magnet  or  load-stone,  is  an  ore  which  is  known 
by  the  name  of  magnetic  iron  ore.  It  occurs  crystal- 
lized, in  regular  octahedrons,  or  in  crystalline  masses,  but 
sometimes  also  in  an  earthy  state.  When  crystallized  it  has 
a  strong  metallic  lustre,  and  a  greyish  black  color.  Its  pe- 
culiar properties  have  been  described  in  Natural  Philosophy, 
Chapter  X. 

Combinations  of  Iron  with  Oxygen,  Chlorine  and  Sulphur. 

§  194.  Iron  has  a  strong  affinity  for  oxygen,  and  forms 
with  it  two  definite  oxides — protoxide  and  per-oxide  of 
iron.  The  chemical  composition  of  the 

Protoxide  of  Iron 

is  1  equivalent  of  iron  =  28 
1         do.     of  oxygen  =    8 


Consequently,  chemical  equiv.  of  protoxide  of  iron  =  36. 

*  Meteor  stones  are  such  as  have  come  down  through  the  atmos- 
phere. Their  origin  is  not  precisely  ascertained.  Some  philosophers 
believe  they  are  of  cosmic  origin  ;  that  is,  so  many  little  globes,  re- 
volving like  our  earth  around  a  common  centre,  which  is  the  sun. 
The  authorities  for  this  opinion  are  Biot,  Chladni,  and  all  German 
mineralogists. 

18* 


210  IRON. 


Per-oxide  of  Iron 

is  composed  of  1    equivalent  of  iron  =  28 
1£       do.      of oxygen  =  12 


Consequently,  chemical  equiv.  of  per-oxide  of  iron  =  40. 

The  Per-oxide  is  obtained  fro  m  a  solution  of  iron  in 
nitric  acid,  which  must  afterwards  be  boiled  and  precip- 
itated by  ammonia.  It  is  of  a  red  color  and  not  attracted 
by  the  magnet.  The  protoxide  may  be  obtained  by  sepa- 
rating part  of  the  oxygen  from  the  per-oxide  which  is  done 
by  passing  hydrogen  over  the  per-oxide,  at  a  temperature  a 
little  below  red  heat.  It  is  blue,  ignites  spontaneously 
when  exposed  to  the  atmosphere,  and  is  attracted  by  the 
load-stone,  though  feebler  than  raw  iron.  When  iron  is 
made  red  hot  in  contact  with  atmospheric  air,  black  oxide  of 
iron  is  formed.,  which  is  an  indefinite  compound  of  iron 
with  oxygen  (a  mixture  of  protoxide  and  per-oxide)  and  an 
abundant  product  of  nature. 

§  195.  Iron  unites  also  with  chlorine  in  two  propor- 
tions. The  respective  products  are  proto-chloride  and  per- 
chloride  of  iron. 

Proto-Chloride  of  Iron 

is  composed  of  1    equivalent   of  iron  =  28 
1       do.      of  chlorine  =  36 


Consequently,  chem.  equiv.  of  proto-chloride  of  iron  =  64. 
Per-Chloride  of  Iron 

is  composed  of  1    equivalent  of  iron  =  28 
1^     do.     of  chlorine  =  54 


Chemical  equivalent  of  per-chloride  of  iron  =  82. 

Proto-chloride  of  iron  is  obtained  from  a  solution  of  iron 
in  muriatic  acid,  which  should  be  evaporated  to  dryness 
and  then  ignited  (secluded  from  the  atmosphere).  The 
product  thus  obtained  is  of  a  grey  color,  has  a  metallic  lustre 
and  scaly  texture.  The  Pcr-chloride  of  iron  is  produced 
by  burning  iron  wire  in  chlorine.  It  is  a  brown  substance, 


IRON.  211 

of  great  lustre.     Both  chlorides  are  used  in  dyeing  —  the 
per-chloride  is  also  employed  in  medicine. 

§  196.  The  sulphurets,  proto-sulpliurets  and  bi-sulphu- 
ret  of  iron  are  products  of  nature.  The  bi-sulphuret,  par- 
ticularly, is  an  abundant  natural  product,  and  is  known  by 
the  name  of  iron  pyrites.  It  is  of  a  yellow  bronze  color, 
somewhat  similar  to  gold  (for  which  it  is  sometimes  mis- 
taken by  those  unacquainted  with  mineralogy)  and  is 
often  found  in  crystals.  It  has  not  as  yet  been  produced 
by  art,  and  when  heated  becomes  converted  into  proto- 
sulphuret  of  iron,  by  losing  half  its  proportion  of  sulphur. 
The  proto- sulphuret  may  also  be  produced  by  rubbing  sul- 
phur on  red-hot  iron.  The  sulphuret  will  fall  down  in 
drops,  which  upon  cooling  are  slightly  attracted  by  the 
magnet. 

Proto-Sulphuret  of  Iron 

is  composed  of  1  equivalent   of  iron  =  28 
1        do.       of  sulphur  =  16 


Consequently,  chemical  equivalent  of  proto-sul- 

phuret  of  iron  =  44. 

Bi-Sulphuret  of  Iron 

is  composed  of  1  equivalent  of  iron  =  28 
2      do.       of  sulphur  =32 


Consequently,  chem.  equiv.  of  bi-sulphuret  of  iron  =  60. 
Combination  of  Iron  with  Carbon,  (Steel). 

§  197.  When  malleable  iron  is  surrounded  by  pow- 
dered charcoal,  and  for  a  length  of  time  exposed  to  a  red 
heat,  part  of  the  carbon,  to  the  amount  of  about  Ti^  part  of 
the  weight  of  iron,  unites  with  the  iron  and  forms  the  well- 
known  substance,  steel.  This  product  of  art,  which  was 
already  known  to  the  ancients,*  is  by  far  more  elastic,  hard 
and  sonorous  than  iron  itself.  In  order  to  adapt  it  to  the 

*  The  Jews,  under  Moses,  knew  the  manufactory  of  steel;  but  in 
the  Trojan  war,  1200  years  before  Christ,  copper  arms  were  used. 


212  LEAD. 

variety  of  purposes  for  which  it  is  used,  it  must  undergo  the 
process  of  tempering  ,  which  consists  in  heating  it  to  a  certain 
point.  According  to  the  different  manners  in  which  steel 
is  manufactured,  and  the  iron  ore  employed  for  that  pur- 
pose, it  is  called  rough  steel,  blistered  steel,  or  cast  steel  ; 
all  which  are  articles  of  commerce.  The  uses  of  steel  for 
the  manufactory  of  surgical  instruments,  razors,  pen- 
knives, scissors,  knives,  forks,  small  and  broad-swords, 
domestic  implements,  carpenters'  and  other  tools,  pens, 
balances  (of  watches),  musical  instruments,  &,c,  are  well 
known,  and  justify  the  assertion  made  in  the  beginning 
of  §193. 

Recapitulation  of  the  principal  Combinations  of  Iron. 

C  protoxide     } 

oxygen  to  <  per-oxide     >  of  Iron. 
(  black  oxide  3 


spi,  i 

^  carbon  to  Steel. 

2.     Lead. 

Chemical  Equivalent  •=  104. 

^  198.  This  well  known  metal  occurs  abundantly 
(though  not  often  in  a  native  state)  in  the  mineral  king- 
dom, and  was,  on  account  of  its  easy  production  from  the 
ores,  known  to  almost  all  people  of  antiquity.  In  its  pure 
state  it  is  of  a  bluish-grey  color,  and  when  recently  cut  has 
a  strong  metallic  lustre.  It  is  very  soft  and  ductile,  but 
on  account  of  its  small  cohesive  attraction  cannot  very  well 
be  drawn  into  wire,  but  may  be  hammered  out  into  plates. 
It  leaves  a  stain  on  paper  or  wood,  and  a  faint,  disagreea- 
ble smell  on  the  fingers.  It  boils  when  exposed  to  a  red 
heat,  and  emits  vapors  which  are  very  injurious  to  health. 
It  is  extensively  used  in  the  manufacture  of  shot,  sugar 
of  lead  (see  Chap.  IV),  and  in  the  process  of  cupellation 
(see  the  next  section). 


LEAD.  213 

Combination     of   Lead    with     Oxygen,    Chlorine,    and 
Sulphur. 

§  199.  Lead  combines  in  four  different  proportions 
with  oxygen.  The  products  are  sub-oxide  of  lead  (ashes 
of  lead)  ;  protoxide  of  lead  (the  massicot  of  commerce)  ; 
deutoxide  of  lead  (red  lead) ;  and  per-oxide  of  lead. 

Chemical  Composition  of  the  Oxides  of  Lead. 
Sub-oxide  of  Lead 

is  composed  of  1    equivalent   of  lead  =  104 
i         do.       of  oxygen  =      4 

Consequently,  chem.  equiv.  of  sub-oxide  of  lead  =  108. 
Protoxide  of  Lead 

is  composed  of  1    equivalent  of   lead  =  104 

1  do.        ofoxygen=      8 

Consequently,  chem.  equiv.  of  protoxide  of  lead  =112. 
Deutoxide  of  Lead 

is  composed  of  1    equivalent  of   lead  =  104 
and   1£       do.       of  oxygen  =    12 

Consequently,  chem.  equiv.  of  deutoxide  of  lead  =  116. 
Per-oxide  of  Lead 

is  a  product  of  1    equivalent  of  lead  =  104 

2  do.      ofoxygen=     16 


Consequently,  chern.  equiv.  of  per-oxide  of  lead  =  120. 

All  these  oxides  may  be  obtained,  though  in  an  impure 
state,  by  heating  lead  in  atmospheric  air,  or  by  the  action 
of  nitric  acid.  They  have  the  peculiar  property  of  com- 
bining with  most  metals,  except  silver,  gold,  and  platinum  ; 
and  are  on  this  account  used  for  purifying  gold  and  silver. 

The  metal  which  is  to  be  purified  is  wrapped  up  in  a  sheet 
of  lead,  and  melted  in  a  crucible.  By  this  process,  which  is 
called  cupellation  (see  §  198),  the  lead  which  is  melted  first 


214  TIN. 

sinks  to  the  bottom  and  carries  along  with  it  all  the  baser  met- 
als with  which  it  combines. 

The  protoxide  of  lead,  or  massicot  of  commerce,  is  obtained 
by  fusing  lead  in  open  vessels,  and  continuing  the  heat  until  it 
has  assumed  a  uniform  yellow  color.  When  this  substance  is 
again  partially  melted,  it  is  called  litharge,  which  however  is 
less  pure  than  the  massicot. 

The  deutoxide  of  lead  is  known  in  commerce  by  the  name 
of  red  lead,  and  is  used  as  a  pigment,  and  in  the  manufactory  of 
glass.  It  is  obtained  by  exposing  massicot  to  a  moderate  heat, 
presenting  a  large  surface  to  the  atmosphere.  At  a  tempera- 
ture equal  to  red  heat  it  parts  again  with  a  portion  of  its  oxy- 
gen and  is  converted  into  protoxide.  When  nitric  acid 
is  poured  upon  the  deutoxide,  it  is  again  partly  converted  into 
a  protoxide,  which  is  dissolved  by  the  acid,  from  which  it  ab- 
sorbs a  further  portion  of  oxygen,  and  is  then  precipitated  in 
form  of  a  dark  brown  powder,  which  is  the  per-oxide. 

Chloride  of  Lead  is  produced  by  adding  common  salt  to  a  so- 
lution of  lead  in  nitric  acid.  It  has  a  sweet  taste,  and  when 
fused  has  the  appearance  of  horn  —  wherefore  it  is  called 
horn  lead.  It  is  composed  of  1  equivalent  of  lead  =  104 

1         do.      of  chlorine  =    36 

Consequently,  chemical  equivalent  of  chloride  of  lead  =  140. 

Sulphuret  of  Lead  (galena)  is  an  abundant  product  of  nature. 
It  is  less  fusible  than  lead,  and  constitutes  the  ore  from  which 
pure  lead  is  commonly  obtained. 

Recapitulation  of  the  principal  Combinations  of  Lead. 
C  sub-oxide  1 


Lead 

combines  with  deutoxide 

chlorine  to  chloride  of  Lead. 
sulphur  to  sulphuret  of  Lead. 

3.      Tin. 

Chemical    Equivalent  =  59. 

§  200.  Tin  is  also  one  of  the  oldest  metals.  It 
was  known  to  the  Phenicians,  who  brought  it  from  Spain 
and  England.  It  was  wrought  in  the  times  of  Moses,  al- 
though it  is  not  a  very  abundant  product  of  nature.  It 


TIN.  215 

occurs  either  as  an  oxide  or  a  sulphuret.  In  its  pure  state 
its  color  resembles  that  of  silver  ;  its  hardness  is  between 
lead  and  gold.  It  may  be  cut  with  a  knife,  is  very  duc- 
tile, may  be  hammered  into  leaves  or  drawn  into  wire,  and 
leaves,  like  lead,  a  faint,  disagreeable  smell  on  the  fingers. 
When  bent  forward  and  backward  it  makes  a  crackling 
noise  ;  but  loses  this  property  when  frequently  repeated. 
It  is  used  for  the  manufactory  of  vessels,  plates,  pots,  ket- 
tles, and  for  tinning  all  kinds  of  sheet-iron  ware. 

Combinations  of  Tin  with  Oxygen,  Chlorine  and  Sulphur. 

§  201.  Tin  has  a  strong  affinity  for  oxygen,  and  com- 
bines with  it  in  two  proportions,  forming  Protoxide  and 
Per-oxide. 

Chemical  Compositions. 
Protoxide  of  Tin 

consists  of  1  equivalent  of  tin  =  59 
1      do.     of  oxygen  =    8 


Consequently,  chemical  equiv.  of  protoxide  of  tin  =  67. 
Per-oxide  of  Tin 

is  composed  of  I    equivalent   of  tin  =  59 
2        do.      of  oxygen  =  16 

Chemical  equivalent  of  per-oxide  of  tin  =  75. 

Both  products  may  be  obtained  by  heating  tin  in  con- 
tact with  the  atmosphere,  or  by  the  action  of  nitric  acid  on 
the  metal. 

When  tin  is  fused,  and  for  a  long  time  in  the  liquid  state,  ex- 
posed to  the  atmosphere,  it  becomes  converted  into  a  grey 
powder,  which  is  the  protoxide.  When  this  is  again  heated 
in  contact  with  air,  it  combines  with  a  further  portion  of  oxy- 
gen, and  is  changed  into  the  per-oxide. 

The  Per-oxide  has  a  light  yellow  color,  becomes  yellow 
at  a  red  heat,  is  infusible,  and  insoluble  in  water,  and 
unites  by  double  affinity  (see  Intro,  page  9)  with  the  al- 
kaline earths.  Oxide  of  tin,  united  with  that  of  lead,  is 


216  COPPER. 

used  in  the  manufactory  of  brass  (see  §  203),  and  for  pol- 
ishing hard  substances,  such  as  glass,  crystal,  stones,  &c. 
Proto- Chloride  of  Tin  is  obtained  by  dissolving  tin-filings  in 
muriatic  acid.  It  is  grey,  half-transparent,  and  soluble  in  wa- 
ter. Per-chloride  of  tin  is  obtained  by  heating  tin-filings  with 
chlorine.  It  is  a  thin,  volatile  liquid,  which  inflames  oil  of 
turpentine  and  emits  white  fumes  when  exposed  to  the  atmos- 
phere. 

Proto-chloride  of  Tin 

is  composed  of  1    equivalent    of  tin  =  59 
1         do.      of  chlorine  =36 


Consequently,  chemical  equiv.  of  proto-chloride  of  tin  =  95. 
Per- Chloride  of  Tin 

is  composed  of  1   equivalent  of    tin  =    59 
2        do.     of  chlorine  =    72 


Consequently,  chemical  equiv.  of  per-chloride  of  tin  =  131. 

§  202.  Of  the  two  sulphurets  of  tin  (Proto-sulphuret 
and  sulphuret)  the  proto-sulphuret  is  produced  by  a  fusion 
of  tin  and  sulphur.  It  is  blue  and  brittle.  The  sulphu- 
ret is  produced  by  heating  per-oxide  of  tin  with  sulphur- 
It  is  used  for  giving  a  beautiful  yellow  color  to  gold. 

Recapitulation  of  the  principal   Combinations  of  Tin. 


comb^with 

«4*r.t. 

4.     Copper. 

Chemical  Equivalent  =  72. 

t203.     Few  metals  have  so  long  been  known  to  man, 
ave  been  wrought  at  so  early  a  period,  as  copper.    (The 
ancients  brought  it  from  the  island  of  Cyper).     It  is  found 
in  a  metallic  state,  connected  with  other  substances,  espe- 


COPPER.  217 

cially  sulphur.  It  is  red,  elastic,  sonorous,  and  when  pure 
has  a  strong  metallic  lustre.  It  has  a  faint,  disagreeable 
smell  and  taste,  and  is  less  coherent  than  iron.  It  is  a 
good  conductor  of  heat,  and  the  best  conductor  of  electri- 
city. It  is  less  fusible  than  silver,  more  so  than  gold, 
becomes  volatile  at  high  degrees  of  heat,  burns  with  a 
green  flame,  becomes  oxidized  in  contact  with  a  damp  at- 
mosphere, and  covered  with  a  green  crust,  which  is  very 
injurious  to  health.  It  is  used  for  the  coverings  of  roofs, 
for  pans  and  pipes  in  breweries,  sugar  refineries,  and  soap- 
manufacturies.  It  is  employed  also  in  the  construction  of 
boilers  for  steam-engines,  for  fastening  vessels,  and  a  va- 
riety of  other  useful  purposes.  One  of  its  chief  applica- 
tions consists  in  uniting  it  with  zinc  in  the  manufactory 
of  brass  and  tombac  ;  and  with  different  proportions  of  tin 
for  the  casting  of  bells,  and  in  the  preparation  of  gun  and 
speculum  metal.  (The  latter  is  used  for  the  construction 
of  reflecting  telescopes,  in  the  manufactury  of  optical  in- 
struments). 

Combinations   of    Copper    with    Oxygen,   Chlorine,   and 
Sulphur. 

§  204.  We  know  of  two  combinations  of  copper  with 
oxygen.  Both  are  products  of  nature,  but  may  be  obtain- 
ed by  burning  copper,  in  a  state  of  minute  division,  in  at- 
mospheric air.  The  protoxide  is  red  and  melts  at  a  red 
heat ;  the  deutozide  is  black  and  tasteless. 

The  protoxide  consists  of  1  equivalent  of  copper  =  72 
and  1         do.       of  oxygen  =    8 

Chemical  equivalent  of  protoxide  of  copper  =  80. 

The  deutoxide  is  composed  of  1  equivalent  of  copper  =  72 

2       do.       of  oxygen  =  16 


Chemical  equivalent  of  deutoxide  of  copper  =  88. 

§  205.  Proto-chloride  and  per-chloride  of  copper  are 
obtained  by  introducing  copper  filings  into  chlorine.  The 
filings  will  spontaneously  take  fire,  and  both  compounds 
are  at  once  produced,  the  proto-chloride  in  a  solid  state, 
and  the  per-chloride  in  form  of  a  powder.  The  proto- 
19 


218  ZINC 

chloride  is  a  yellowish  substance,  similar  in  appearance  to 
resin,  easily  fusible,  but  insoluble  in  water.  The  per- 
chloride  is  a  brown  powder,  which,  when  it  has  absorbed 
moisture  from  the  air,  turns  green.  Spirits  of  wine,  in 
which  per-chloride  of  copper  has  been  dissolved,  burns 
with  a  beautiful  green  flame,  on  account  of  which  it  is 
used  in  fire-works  and  for  theatrical  purposes. 

Proto-Chloride 

is  composed  of  1  equivalent    of  copper  =    72 
1         do.        of  chlorine  =    36 


Consequently,  chemical  equivalent  of  proto-chlo- 

ride  of  copper  =  108. 

Per-Chloride  of  Copper 

is  composed  of  1   equivalent  of  copper  =    72 
2         do.        of  chlorine  =    72 


Chemical  eqvivalent  of  per-chloride  of  copper  =  144. 

The  Sulphurets  of  copper  (proto-sulphuret,  and  bi-sul- 
phuret)  are  abundant  products  of  the  mineral  kingdom. 
The  former  is  found  combined  with  other  sulphurous  met- 
als, the  latter  has  been  discovered  near  the  crater  of  Mount 
Vesuvius,  and  in  a  few  rare  copper  ores. 

Recapitulation  of  the  principal  Combinations  of  Copper. 


of  Copper. 
of  Copper. 


Copper          )    , ,    .  5  proto-chloride 

combines  with  \  chlonne  to    \per-chloride 

7  i      t    S  proto-sulphuret 
mlPhurio  \bi-sulphurtt 

5.     Zinc. 


Chemical  Equivalent  =  34. 

§  206.  The  ore  of  this  metal  was  formerly  imported 
into  Europe  from  China.  In  the  J6th  century  it  was  dis- 
tinguished as  a  separate  metal,  and  received  its  present 


BISMUTH.  219 

appellation.  It  is  not  found  in  a  native  state,  but  occurs 
mixed  with  lead  or  sulphur.  (Most  zinc  is  obtained  from 
an  ore  called  sparry  calcimine,  which  is  a  carbonate  of  this 
metal).  Pure  zinc  has  a  bluish-white  color  and  a  strong 
metallic  lustre.  It  is  less  ductile  than  lead  or  tin,  but  when 
heated  to  from  212  to  302°  Fahrenheit  it  may  be  ham- 
mered, or  drawn  into  wire.  Of  all  metals  which  are  used 
in  common  life,  it  is  most  expanded  by  heat.  It  is  capable 
of  volatilization  and  distillation  by  heat. 

Combinations  af  Zinc  with  Oxygen  and  Chlorine. 

§  207.  Zinc  may  be  burnt  in  atmospheric  air  or  chlo- 
rine. In  the  first  case  the  combustion  is  accompanied  by 
a  most  beautiful  blue  flame,  into  which  the  forming  oxide 
of  zinc  is  thrown  up  in  form  of  white  flakes,  formerly 
known  by  the  name  of  flowers  of  zinc.  In  the  second 
case  chloride  of  tin  is  formed,  which  is  a  soft,  grey  sub- 
stance, of  the  consistency  of  wax,  easily  soluble  in  water, 
and  used  (in  France)  in  the  process  of  dyeing. 

Oxide  of  Zinc 

is  composed  of  1    equivalent   of   zinc  =  34 
1         do.         of  oxygen  =    8 

Consequently,  chemical  equivalent  of  oxide  of  zinc  =  42. 
Chloride  of  Zinc 

is  composed  of  I    equivalent  of  zinc  =  34 
1         do.      of  chlorine  =  36 


Consequently,  chemical  equiv.  of  chloride  of  zinc  =  70. 
Recapitulation  of  the  principal  Combinations  of  Zinc. 

^  oxygen  to  oxide        } 

Zinc  combines  with  2  V  of  Zinc. 

(  chlorine  to  chloride  ) 

6.     Bismuth. 

Chemical  Equivalent  =  71. 
§  208.     Bismuth  is  seldom  found  in  its  native  state ;  it 


220  COBALT. -ANTIMONY. 

is  more  frequently  combined  with  oxygen,  sulphur  and 
lead.  It  has  a  reddish-white  color,  and  a  strong  metallic 
lustre.  It  is  very  brittle,  so  that  it  may  be  reduced  to  a 
powder,  is  fusible,  volatile,  and  capable  of  distillation.  It 
is  used  for  the  manufactury  of  pigments  and  paints.  It 
combines  with  oxygen  and  chlorine  to  oxide  and  chloride 
of  bismuth,  in  a  manner  similar  to  zinc  (see  the  last  sec- 
tion). Its  principal  binary  combinations  may  therefore  be 
arranged  as  follows  : 

oxygen  to   oxide      ") 

Rismuth  combines  with  1  V  of  Bismuth, 

chlorine  to  chloride  ) 

7,     Cobalt. 

Chemical  Equivalent  not  asr.erlained. 

§  209.  The  ores  of  Cobalt  were  already  known  in  the 
15th  century,  and  used  in  the  manufactury  of  blue  pig- 
ments. It  is  however  but  a  few  years  since  cobalt  has  been 
entirely  separated  from  nickel,  arsenic  and  iron,  with 
which  it  is  commonly  found  combined.  The  purest  cobalt 
is  of  a  greyish-white  color  (between  silver  and  steel),  and 
possesses  considerable  splendor.  It  is  malleable  and  duc- 
tile only  in  an  inferior  degree  (cannot  be  drawn  into  wire), 
is  attracted  by  the  magnet,  and  capable  of  receiving  mag- 
netic properties  (Nat.  Phil.  Chap.  X).  The  oxides 
of  this  metal,  which  are  obtained  by  exposing  it  to  an  in- 
tense heat  in  contact  with  atmospheric  air,  or  by  precipit- 
ating it  from  a  solution  in  nitric  acid,  by  the  addition  of 
potash,  occur  in  commerce  mixed  with  sand  or  calcined 
flint,  under  the  name  of  zaffer  and  smalts.  They  are  fine 
blue  pigments,  and  are  extensively  used  for  dyeing  linen, 
or  to  stain  glass  and  China. 

8.      Antimony. 
Chemical  Equivalent  =  44. 

§  210.  Antimony  occurs  either  native,  or  in  red  and 
grey  ore  of  antimony.  It  has  a  dusky  white  color,  consid- 


ANTIMONY.  221 

erable  metallic  lustre  and  scaly  fracture.  It  is  so  brittle 
that  it  may  be  reduced  to  a  powder,  is  fusible  and  volatile, 
and  burns  when  heated  in  the  atmosphere.  It  is  used  as 
an  alloy  in  some  of  the  arts,  and  sometimes  it  is  employed 
in  medicine.  Combined  with  lead  it  forms  the  metal  of 
which  printers'  type  is  cast. 

Combinations   of  Antimony  with    Oxygen,  Chlorine   and 
Sulphur. 

§  211.  Antimony  combines  with  oxygen  in  three  dif- 
ferent proportions.  The  first  of  these  combinations, 

Protoxide  of  Antimony, 

is  composed  of  1  equivalent  of  antimony  =  44 
1         do.          of  oxygen  =3    8 

Its  chemical  equivalent,  therefore,  is  =  52. 

It  is  a  product  of  nature,  but  may  be  obtained  also  by 
the  combustion  of  antimony  in  atmospheric  air.  It  is  a 
greyish  white  powder,  which,  when  taken  into  the  stom- 
ach, operates  like  an  emetic,  melts  at  a  red  heat,  is  vola- 
tile, and  forms,  upon  cooling,  regular  crystals.  The  second, 

Deutoxide  of  Antimony  (Antimonious  Acid), 

is  composed  of  1  equivalent  of  antimony  =  44 
1J         do.         of  oxygen  =  12 


Consequently,  chem.equiv.  of  deutoxide  of  antimony  =  56. 

It  is  found  in  some  of  the  ores  of  antimony,  and  may  be 
formed  by  heating  the  protoxide  in  the  open  air.  It  is  a 
white  powder  without  smell  er  taste,  insoluble  in  water, 
and  fusible  only  when  submitted  to  high  degrees  of  heat. 
It  is  used  in  glass  and  porcelain  painting.  The  third, 

Per-oxide  of  Antimony, 

is  a  product  of  1  equivalent  of  antimony  =  44 
and  2          do.          of  oxygen  =  16 


whence  its  chemical  equivalent  is  =  60. 
19* 


222  ARSENIC. 

It  is  formed  by  pouring  a  solution  of  antimony  in  nitro- 
muriatic  acid,  see  (§  185,  page  202)  upon  water  ;  the  per- 
oxide is  then  precipitated.  It  is  of  a  yellow,  straw-color, 
inodorous  and  tasteless,  and  when  submitted  to  a  red  heat 
parts  with  some  portion  of  its  oxygen,  and  is  again  con- 
verted into  the  deutoxide. 

The  Proto- chloride  or  butter  of  Antimony,  is  obtained  by  the 
combustion  of  powdered  antimony  in  chlorine.  It  is  soft,  and 
melts  at  a  gentle  heat.  The  per-chloride  is  produced  by 
bringing  heated  solid  antimony  in  contact  with  chlorine. 

Antimony  combines  yet  readily  with  sulphur.  The  com- 
pound is  a  grey  sulphuret,  with  metallic  lustre,  and  is,  among 
all  the  ores  of  antimony,  that  which  is  most  abounding  in  nature. 

Recapitulation  of  the  principal  Combinations  of  Antimony. 

C  protoxide  } 

oxygen  to  <  deutoxide  >  of  Antimony. 
Antimony      1  ( per-oxide ) 

combines  with        m.neto    \P^^  ^  Antony. 

sulphur  to  sulphuret  of  Antimony. 

9.     Arsenic. 

Chemical  Equivalent  =  38. 

§  212.  Arsenic*  was  first  obtained  from  arsenic  acid 
by  Brandt,  a  celebrated  chemist,  in  1733.  It  occurs  com- 
bined  with  various  substances  in  the  mineral  kingdom.  It 
is  of  the  color  of  steel,  and  has  a  strong  metallic  lustre, 
which,  however,  is  easily  tarnished.  Its  texture  is  lamellar. 
At  356°  Fahrenheit  it  forms  greyish  white  vapors,  which 
have  a  strong  smell  of  garlic.  It  has  a  strong  affinity 
for  oxygen  (powdered  arsenic  moistened  with  water  may 
be  heated  to  spontaneous  combustion).  In  oxygen  gas  it 
burns  with  a  bluish  white  flame,  leaving  arsenic  acid.  It 
is  poisonous,  although  less  so  than  the  acid.  Its  use  in  the 
arts  is  very  limited. 

*  What  iii  commerce  occurs  as  Jlrsenic,  is  arsenic  acid,  or  oxide 
of  arsenic. 


ARSENIC.  223 

Combinations   of  Arsenic  with    Oxygen,   Hydrogen   and 
Sulphur. 

§  213.  We  know  of  three  different  combinations  of 
arsenic  with  oxygen.  The  first, 

Oxide  of  Arsenic,  is  an  indefinite  compound,  formed  by 
the  contact  of  the  metal  with  atmospheric  air,  and  consists 
of  a  dark  grey  powder.  The  second, 

Arsenious  Acid, 

is  composed  of  1  equivalent  of  arsenic  =3  38 
and  2  equivalents  of  oxygen  (each  =  8)  =  16 


Consequently,  chemical  equiv.  of  arsenious  acid  =  54. 

It  is  a  product  of  nature.  It  is  white,  brittle,  and  high- 
ly poisonous.  It  tastes  sweetish,  is  sparingly  soluble  in 
water,  but  when  heated  is  easily  volatilized.  It  is  used  in 
medicine  and  in  some  of  the  arts  ;  viz  :  in  glass  factories, 
in  cotton-printing,  and  in  the  preparation  of  mineral  green. 
It  may  also  be  employed  to  preserve  stuffed  animals 
from  destructive  insects.  The  third  combination  of  arse- 
nic with  oxygen, 

Arsenic  Acid, 

is  composed  of  1  equivalent  of  arsenic  =  38 
3         do.         of  oxygen  =  24 


Consequently,  chemical  equivalent  of  arsenic  acid  =  62. 

It  occurs  in  some  mineral  salts.  It  may  be  obtained, 
also,  by  the  action  of  nitric  acid  on  heated  arsenious  acid. 
It  is  a  white,  opaque,  inodorous  mass,  with  a  pungent, 
sour  taste,  and  still  more  poisonous  than  arsenious  acid. 

Arseniuretted  Hydrogen. 
Chemical  Equivalent  not  ascertained. 

§  214.  A  combination  of  arsenic  with  hydrogen  is 
called  arseniuretted  hydrogen  gas.  It  is  a  colorless  gas 
of  a  nauseous  smell.  When  taken  into  the  lungs  it  causes 
giddiness,  oppression,  and  death. 


224  MANGANESE. 

Sulphuret  of  arsenic  is  a  product  of  nature.  It  occurs 
in  commerce  under  the  name  of  Realgar,  and  is  used  in 
dyeing  and  calico-printing. 

Recapitulation  of  the  principal  combinations  of  Arsenic. 

C  oxide  of  arsenic. 
\  oxygen  to  2  arsenious  acid. 
Arsenic  combines  with  '  f  arsenicacid. 

I  hydrogen  to  arseniuretted  hydrogen  gas. 
\  sulphur  to  sulphur  et  of  arsenic. 

10.     Manganese. 

Chemical  Equivalent  =  28. 

§  215.  Manganese  occurs  as  an  oxide  or  sulphuret, 
sometimes  also  in  combination  with  chlorine  or  arsenic. 
It  is  of  a  greyish  white  color,  and  has  a  strong  metallic 
lustre.  It  is  hard,  brittle,  becomes  easily  oxydized,  and 
falls  to  powder.  It  decomposes  water  at  common  temper- 
atures, and  melts  when  submitted  to  superior  degrees  of 
heat.  Little  application  is  made  of  this  metal  in  the  arts. 

Combinations  of  Manganese  with   Oxygen  and  Chlorine. 

§  216.  Manganese  combines  with  oxygen  in  4  or  5 
different  proportions.  Two  of  them  are  indefinite  com- 
pounds, or  mixtures  of  the  protoxide,  deutoxide,  and  per- 
oxide, and  neither  of  them  is  of  much  service  to  the  arts. 
The  pcr-oxide  is  an  abundant  product  of  nature,  has  an 
earthy  appearance  (sometimes  black,  in  crystals)  and  is 
soluble  in  water.  It  is  used  in  the  preparation  of  chlorine 
for  bleaching,  and  constitutes  what  is  called  the  glass- 
makers'  soap.  From  the  per-oxide  the  deutoxide  and 
protoxide  may  be  obtained  by  heat.  By  mixing  it  with 
nitre,  and  submitting  it  to  red  heat,  an  acid  is  obtained, 
which  is  called  manganesis  acid. 

Chloride  of  manganese  is  found  in  some  mineral  waters 
and  may  be  obtained  by  a  direct  combination  of  manga- 
nese with  chlorine.  It  is  a  red  liquid,  which  is  used  for 
the  brown  ground  in  calico  printing. 


TELLURIUM.  — TITANIUM.— CERIUM.  225 

Recapitulation  of  the  principal  combinations  of  Manganese. 

/-  C  protoxide  } 

JVf,_e     \  oxygen  to  )  £^£  ^  ^"^ 
combines  with  }  (  L^imm'c  acid. 

{chlorine  to  chloride  of  Manganese. 

11.       Tellurium* 
Chemical  Equivalent  =  29. 

§  217.  Tellurium  has  but  recently  been  discovered  in 
one  of  the  ores  of  Transylvania.  It  occurs  seldom,  either 
native  or  mixed  with  gold,  silver,  lead,  and  bismuth. 
It  possesses  a  greyish  white  color,  a  strong  metallic  lustre, 
and  a  lamellar  texture.  It  is  brittle,  may  easily  be  redu- 
ced to  a  powder,  boils  when  submitted  to  superior  degrees 
of  heat  and  is  capable  of  distillation.  Of  all  metals  it  is 
the  worst  conductor  of  electricity.  It  combines  with  oxy- 
gen and  hydrogen.  No  use  is  made  of  this  metal  or  its 
compounds  in  the  arts. 

12.      Titanium. 
Chemical  Equivalent  not  ascertained. 

§  218.  This  metal  never  occurs  in  its  simple  form, 
but  is  found  crystalized  in  scales  of  a  copper-brown  color, 
in  the  slags  of  smelting-furnaces  ;  a  small  quantity  of  ti- 
tanium being  often  contained  in  iron.  It  is  hard  and  brittle, 
scratches  steel,  and  is  capable  of  a  high  polish.  It  is  not 
fusible  at  a  common  red  heat,  and  is  under  common  cir- 
cumstances, not  acted  upon  by  any  acid.  It  combines  in 
two  or  three  proportions  with  oxygen,  which  are  not  easily 
reduced  to  the  metallic  state. 

13.     Cerium. 

Chemical  Equivalent  supposed  to  be  =  50. 
§  219.     This  metal  occurs  but  sparingly  in  form  of  an 

*  The  remaining  part  of  this  chapter  may  be  omitted  by  young 
pupils  until  reviewing  the  book. 


226          URANIUM.  — COLUMBIUM.  — TUNGSTEN. 

oxide  from  which  it  has  been  obtained  in  exceeding  small 
quantities  by  the  action  of  very  powerful  voltaic  batteries. 
It  is  a  chocolate-colored  powder,  which  a  little  before  red 
heat  ignites  and  burns  vividly,  the  product  of  the  combus- 
tion being  an  oxide  of  the  metal. 

14.      Uranium. 
(Not  precisely  ascertained). 

§  220.  Uranium  is  obtained  by  the  action  of  hydro- 
gen upon  the  heated  oxide  of  uranium.  It  is,  like  cerium, 
of  rare  occurrence,  consists  of  a  brown  powder,  which 
when  polished  shows  a  greyish  dark  lustre.  It  combines 
in  two  proportions  with  oxygen.  The  two  products  of 
these  combinations,  protoxide  and  per-oxidc  of  uranium, 
are  employed  in  porcelain  painting,  the  first  gives  it  a 
black,  and  the  second  an  orange  color. 

15.     Columbium. 

Chemical  Equivalent  =144. 

§  221.  This  metal  was  discovered  by  Hatchet,  in  an 
American  fossil  (wherefore  its  name),  it  is  found  very 
sparingly  in  form  of  an  acid,  from  which  it  is  extracted. 
It  is  a  black  powder,  which,  when  polished,  becomes  of 
the  color  and  lustre  of  iron.  In  thin  leaves  it  is  a  con- 
ductor of  electricity  and  is  acted  upon  by  boiling  nitro- 
muriatic  acid.  Its  only  combination  with  oxygen  is,  as 
we  have  just  said,  an  acid,  from  which  the  metal  itself  is 
obtained. 

16.      Tungsten  (  Wolfram). 

Chemical  Equivalent  =  96. 

§  222.  Tungsten  is  obtained  from  tungstic  acid,  the 
only  form  in  which  it  occurs  in  some  fossils.  It  is  a  dark 
grey  powder,  which  by  polishing  can  be  made  to  assume 
a  weak  metallic  lustre.  It  is  very  infusible.  When  sub- 


CADMIUM.  — CHROMIUM.  227 

mitted  to  red  heat  in  contact  with  atmospheric  air,  it  be- 
comes oxydized,  and,  in  small  portions,  is  capable  of  igni- 
tion. It  combines  in  two  proportions  with  oxygen,  forming 
an  oxide  and  an  acid.  The  latter  is  a  product  of  nature  ; 
the  oxide  is  obtained  by  reducing  the  acid,  through  the  ac- 
tion of  hydrogen  gas. 

17.  Cadmium. 

Chemical  Equivalent  =  56. 

§  223.  This  metal  is  contained  in  the  ores  of  zinc, 
from  which  it  is  obtained  chiefly  be  distillation.  It  resem- 
bles zinc  in  color  and  properties  ;  but  is  more  malleable 
and  ductile.  It  may  be  drawn  into  wire  or  reduced  to 
thin  plates.  It  melts  a  little  before  red  heat,  and  burns  to 
a  brown  oxide,  the  only  compound  of  cadmium  and  oxy- 
gen known.  A  combination  of  this  metal  with  sulphur, 
which  is  not  unfrequently  found  in  a  natural  state,  is  of  a 
beautiful  yellow  color  (turning  into  orange),  and  has  lately 
been  employed  in  oil-painting.* 

18.  Chromium. 
Chemical  Equivalent  =  28. 

^  224.  Chromium  is  found  only  in  an  oxydized  state, 
in  the  red  ore  of  lead  and  in  combination  with  iron,  from 
which  it  is  extracted  by  heat.  It  is  of  a  greyish-white 
color,  very  brittle,  but  sparingly  soluble  in  boiling  nitro- 
muriatic  acid,  and  combines  with  oxygen  in  three  propor- 
tions, forming  protoxide  of  chromium,  deutoxide  of  chro- 
mium,  and  chromic  acid. 

The  protoxide  is  a  product  of  nature,  and  may  be  ob- 
tained by  heating  chromium  in  contact  with  air.  It  is  a 
dark  green  powder,  infusible,  and  insoluble  in  water  ;  and 
is  used  in  porcelain  and  oil-painting.  Deutoxide  of  Chro- 
mium is  produced  by  the  action  of  sulphuric  acid  on  chro- 

*  An  Kalian  painter  by  the  name  of  Demin,  employed  it  lately  in  a 
painting  (Alfresco),  and  found  it  very  applicable. 


228         MOLYBDENUM.  — VANADIUM. 

mic  acid.  It  is  a  dark-brown  powder  of  little  lustre,  which 
when  heated  gives  off  oxygen.  Chromic  acid  is  a  product 
of  nature.  It  is  commonly  found  combined  with  lead, 
from  which  it  is  obtained  by  a  somewhat  difficult  process. 
It  is  of  a  red  color  (when  dissolved  in  water  and  distilled, 
it  forms  beautiful  ruby-colored  crystals),  has  a  sharp,  sour 
(rather  astringent)  taste,  stains  the  skin  yellow,  and  is 
dissolved  in  contact  with  the  atmosphere,  in  water  or  al- 
cohol. 

1 9.  Molybdenum. 

Chemical  Equivalent  =  48. 

§  225.  Molybdenum  occurs  only  in  small  quantities, 
in  combination  with  oxygen,  sulphur  and  lead.  It  is  com- 
monly obtained  by  reduction  of  the  heated  oxide,  through 
hydrogen  gas.  It  is  hard  and  brittle,  and  burns  when 
heated  in  the  air,  to  Molybdic  Acid.  It  combines  yet  in 
two  other  proportions  with  oxygen  forming  an  oxide  and  a 
Molybdous  acid.  No  application  is  made  of  this  metal  or 
its  binary  compounds  in  the  arts. 

20.  Vanadium. 

Chemical  Equivalent  not  ascertained. 

§  226.  This  metal  was  discovered  (by  Sesstrom)  in 
1830.  It  has  been  found  in  some  of  the  ores  of  iron  and 
lead,  in  Eckersholm  in  Sweden,  and  Ximapar  in  Mexico. 
The  process  of  procuring  it  is  tedious  and  difficult.  It  is 
obtained  in  white  leaves  of  a  strong  metallic  lustre.  It  is 
so  brittle  that  it  cannot  be  hammered,  and  does  not  become 
oxydized  at  common  temperatures,  neither  in  atmospheric 
air  or  in  water.  It  is  soluble  in  muriatic  and  nitro-muri- 
atic  acid,  and  combines  in  three  different  proportions  with 
oxygen,  forming  two  oxides  and  one  acid.  It  enters  also 
into  combinations  with  sulphur  and  chlorine. 


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232  RECAPITULATION 

RECA  PITULATION. 

Questions  for  Reviewing  the  most  important  Principles 
contained  in  the   Third  Chapter. 

1.  QUESTIONS  ON  THE  PRELIMINARY  REMARKS  ON  METALS. 

[§  137.]  Is  it  possible  to  fix  with  precision  upon  the 
general  characteristics  of  metals?  By  what  properties  are 
they,  notwithstanding,  more  or  less  distinguishable  ? 

Are  the  metals  commonly  electro-positive  or  electro  -negative 
bodies  ?  Why  ? 

[§  138.]  To  what  class  of  bodies  do  all  metals  belong, 
as  far  as  our  experience  goes  in  chemistry  1  What  is  their 
number  ?  What  are  their  names  ? 

[§  139.]  For  what  substance  have  all  metals  a  greater 
or  less  affinity  ?  Under  what  circumstances  do  they  com- 
bine with  oxygen  ? 

What  change  is  wrought  upon  most  metals  when  they  are 
exposed  to  air  or  to  moisture  ?  By  what  is  this  change  occa- 
sioned ?  To  what  is  the  increase  of  weight  proportional  ? 
Which  metal,  more  than  all  others,  attracts  oxygen  from  the 
air  and  from  moisture  ?  What  is  the  friable  substance  called, 
which  collects  on  the  surface  of  iron  ?  How  are  metals  pre- 
vented from  rusting  ?  What  was  Davy's  proposition  for  pre- 
venting metals  from  rusting?  Why  are  steel  instruments 
kept  in  silver  paper  ? 

[§  140.]  Is  oxygen  the  only  substance  with  which 
metals  combine  ?  Into  what  other  combinations  do  the 
metals  yet  enter  ?  What  are  the  products  of  these  respec- 
tive combinations  called  ? 

[§  141.]  What  do  you  understand  by  alloys  of  metals  1 
What  by  amalgams  ?  What  properties  do  the  alloys  of 
metals  generally  possess  ? 

[§  142.]  What  may  be  done  with  two  metals  possessing 
different  degrees  of  fusibility  ?  Why  is  fusion  a  means  of 
refining  ores  ? 


OF    CHAPTER    III.  233 

[§  143.]  What  are  metals  which  easily  melt  capable 
of  advancing  in  others  ?  What  process  is  founded  upon 
this  property  of  the  metals  ?  In  what  consists  the  process 
of  soldering  ? 

What  solder  is  employed  for  tin  ware  ? 

What,  for  cast  iron  ? 

What,  for  copper  and  brass  ? 

How  is  zinc  soldered  ? 

How,  platinum  ? 

How,  gold? 

What  solder  is  used  for  silver  ? 

[<§  144.]  What  other  process  of  art  is  founded  upon 
the  natural  attraction  which  exists  between  some  of  the 
metals  ? 

Give  examples. 

[§  145.]  In  what  state  are  the  metals  generally  found  ? 
What  are  they  then  called  1  Where  do  they  occur  ?  In 
what  are  they  generally  bedded  1  What  are  those  sub' 
stances  called  with  which  the  metals  are  commonly  found 
combined  1  What  substance  is  most  abundantly  found 
combined  with  the  metals  1  What  is  it  therefore  called  1 
What  are  those  metals  called  which  occur  in  their  simple 
form  ?  Where  is  native  gold  and  silver  principally  found  ? 

[§  146.]  What  is  the  process  called  by  which  the 
pure  metal  is  extracted  from  the  ore  1  What  means  are 
particularly  resorted  to  for  this  purpose  ? 

In  what  consists  the  roasting  of  ores  ? 

In  what  the  smelting  of  ores  ? 

In  what  the  refining  of  metals  ? 

[§  147.]  What  do  the  similar  properties  which  some 
metals  possess  enable  us  to  do  1 

To  what  class  of  metals  belong  potassium,  sodium,  lithi- 
nm,  calcium,  barium,  and  strontium  ? 

What  is  the  name  applied  to  the  metals,  magnesium^ 
yttrium,  alumium,  glucinum,  zirconium,  and  thorium  ? 

What  are  the  names  of  the  nine  noble  metals? 

What  metals  are  most  useful  to  man  ? 

20* 


234  RECAPITULATION 


A.     QUESTIONS  ON  THE  six  ALKALINE  METALS. 

[§  148.]  What  is  the  chemical  equivalent  of  potas- 
sium ?  How  may  this  metal  be  obtained  ? 

How  large  a  galvanic  battery  is  required  for  the  decomposi- 
tion of  hydrate  of  potash  1  Describe  the  process  by  which 
Thenard  and  Gay-Lussac  decomposed  hydrate  of  potash  in  a 
bent  gun-barrel.  (Explain  Fig.  CXII). 

[§  149.]  What  are  the  characterizing  properties  of 
potassium  ? 

[§  150.]  In  how  many  different  proportions  does  po- 
tassium combine  with  oxygen  ?  Which  is  the  most  re- 
markable of  these  combinations  ?  What  is  its  chemical 
composition  ?  Where  does  it  occur  1  How  may  it  be  ob- 
tained pure,  by  art  ? 

How  is  the  potash  of  commerce  obtained?  What  does 
potash  form  when  united  with  water  ?  What  substance  does 
this  hydrate  form  in  combination  with  the  fat  oils? 

[§  151.]  What  are  the  properties  of  the  hydrate  of 
potash  ?  How  is  it  obtained  ? 

[§  152.]  What  is  the  name  given  to  a  solution  of  hy- 
drate of  potash  ?  What  are  its  properties? 

[§  153.]  To  what  compound  does  potassium  unite  with 
chlorine  ?  What  is  the  chemical  composition  of  chloride 
of  potassium  ?  Where  is  it  found  ?  How  may  it  be  pro- 
duced by  art  ?  What  are  its  properties  1 

What  are  the  principal  binary  combinations  of  Potas- 
sium ? 

[§  154.]  What  is  the  chemical  equivalent  of  sodium  ? 
In  what  manner  is  sodium  obtained  1  What  are  its  prop- 
erties 1  For  what  substance  has  sodium  a  strong  affinity  ? 

[§  155.]  What  is  the  chemical  composition  of  soda  ? 
In  how  many  different  proportions  does  sodium  combine 
with  oxygen  1  Where  does  protoxide  of  sodium,  or  soda 
occur  ?  How  is  the  purest  soda  obtained  ?  What  are  its 
properties  1 


OF    CHAPTER    III.  235 

[§  156.]  What  is  the  chemical  composition  of  chloride 
of  sodium,  or  common  salt?  Where  does  it  occur  1  In 
what  is  it  also  largely  contained  ?  By  what  means  may 
it  be  procured  in  its  purest  state  ?  In  what  form  does  it 
crystalize  ?  What  does  it  constitute  ? 

WJiatare  the  principal  binary  combinations  of  Sodium  ? 

157.]  What  is  the  chemical  equivalent  of  lithium  ? 
ow  is  lithium  obtained  ?  What  are  its  properties  ? 
What  is  the  chemical  composition  of  the  oxide  of  lithium, 
or  lithia  1 

[§  158.]  What  is  the  chemical  equivalent  of  calcium? 
By  what  means  is  calcium  obtained  ?  What  is  the  pro- 
toxide of  calcium  called  ?  What  is  the  chemical  equiva- 
lent of  lime  ?  Where  does  it  occur  ?  How  may  it  be 
obtained  pure  ? 

[§  159.]  What  are  the  principal  properties  of  lime  ? 
Why  is  lime  said  to  be  a  flux  1  What  is  the  taste  of  lime  ? 
Into  what  does  it  become  converted  by  the  process  of 
slaking  ? 

What  are  the  principal  uses  of  lime  ? 

What  substance  does  calcium  form  in  combination  with 
chlorine  ? 

What  are  the  two  principal  binary  combinations  of 
Calcium  ? 

[§  160.]  What  is  the  chemical  equivalent  of  barium  ? 
By  what  process  is  barium  produced  ?  What  are  its  prop- 
erties ?  In  how  many  different  proportions  does  it  com- 
bine with  oxygen  ?  What  is  the  protoxide  of  barium  call- 
ed ?  What  is  its  chemical  composition  ? 

[§  161.]  What  are  the  leading  properties  of  baryta? 
What  are  the  properties  of  baryta-water  ? 

What  kind  of  substance  is  the  per-oxide  of  barium  ? 

With  what  other  substances  is  barium  known  to  com- 
bine ? 

What  are  the  principal  binary  combinations  of  Barium  1 


236  RECAPITULATION 

[§  162.]  What  is  the  chemical  equivalent  of  strontium  ? 
How  is  it  procured  ?  What  are  its  properties  1  In  how 
many  proportions  does  it  combine  with  oxygen  ?  In  what 
state,  and  where  is  the  protoxide  of  strontium,  or  strontia, 
generally  found  ?  What  is  its  chemical  composition  ? 
What  are  its  properties  1  With  what  other  substances 
does  strontium  yet  combine  ? 

What  are  the  most  remarkable  binary  combinations  of 
Strontium  1 

B.     QUESTIONS  ON  THE  six  EARTHY  METALS,  MAGNESIUM, 

YTTRIUM,  ALUMIUM,  GLUCINUM,  ZIRCONIUM, 

AND  THORIUM. 

[$  163.]  Is  the  existence  of  the  six  earthy  metals 
proved  by  actual  experiment?  Under  what  names  were 
the  oxides  of  these  metals  formerly  known  ?  What  do  the 
experiments  which  have  been  made  upon  them,  together 
with  the  strong  analogy  which  exists  between  them  and 
the  alkaline  metals  prove  them  to  be  ?  By  what  partic- 
ular test  are  all  of  them  distinguished  ?  How  do  they 
all  act  upon  the  acids  ? 

[§  164.]  What  is  the  chemical  equivalent  of  magne- 
sium ?  By  what  means  may  magnesium  be  obtained  ? 

Explain  this  process  by  galvanic  electricity.  Explain  the 
process  in  which  the  metal  is  obtained  from  the  chloride  of 
magnesium. 

What  are  the  properties  of  magnesium ,  obtained  by  either 
of  these  processes  ?  In  how  many  proportions  does  it 
combine  with  oxygen  ?  What  is  the  compound  called  ? 
What  is  its  chemical  composition  ? 

[§  165.]  Where  does  the  oxide  of  magnesium  occur  ? 
From  what  substance  is  magnesia  obtained  for  commerce  1 
By  what  means  is  it  obtained  in  its  purest  state  ? 

What  are  the  properties  of  magnesia  ? 

What  sort  of  substance  is  chloride  of  magnesium? 

What  are  the  principal  binary  combinations  of  Magne- 
sium ? 


OF    CHAPTER    III.  237 

[§  166.]  What  is  the  chemical  equivalent  of  gluci- 
num  ?  How  is  this  metal  produced  1 

Explain  the  process. 

By  what  sort  of  reasoning  are  we  led  to  the  inference  that 
the  dark  colored  globules  which  in  your  experiment  ap- 
pear disseminated  throughout  the  whole  mass,  are  actually  the 
metal  glucinum  ?  What  strong  analogy  does  glucina  bear  to 
those  substances  which  we  know  to  be  oxides  of  metals? 

What  are  the  properties  of  glucinum  ? 

Where  does  the  oxide  of  glucinum,  or  glucina  occur  ? 
What  sort  of  substance  is  it  1  What  is  its  chemical 
equivalent  supposed  to  be  ? 

167.]     What  is  the  chemical  equivalent  of  yttrium? 
ow  is  this  substance  obtained  1 
What  are  its  properties  ? 

Where  is  the  oxide  of  yttrium  found  ?  What  is  it  call- 
ed ?  By  what  peculiarity  are  all  the  salts  of  yttria  dis- 
tinguished ? 

[§  168. ]  What  is  the  chemical  equivalent  of  alumium  ? 
What  are  its  properties  1 

What  is  the  chemical  composition  of  alumia? 

[§  169.]  Where  does  alumia  occur?  In  what  sub- 
stances is  it  contained  in  its  simple  form  ?  What  are  its 
properties  ?  For  what  purposes  is  it  used  ?  With  what 
substances  does  alumium  yet  combine  ? 

What  are  the  principal  binary  combinations  of  Alum- 
ium ? 

[§  170.]  By  what  means  has  zirconium  been  obtained 
in  its  simple  form  ?  What  are  its  properties  ? 

Where  has  the  oxide  of  zirconium,  or  zirconia  been 
found  ?  What  are  its  properties  ? 

[§  171.]  By  what  means  was  thorium  produced? 
What  are  its  properties  ?  Where  is  the  oxide  of  thorium 
found  ? 


238  RECAPITULATION 

C.     QUESTIONS  ON  THE  NINE  NOBLE  METALS,  MERCURY, 
SILVER,  GOLD,  PLATINUM,  PALLADIUM,  RHODIUM, 
IRIDIUM,  OSMIUM,  AND  NICKEL. 

[§  172.]  What  is  the  chemical  equivalent  of  mercury  ? 
Where  does  mercury  occur  ? 

How  is  mercury  obtained  from  the  ore  ? 

[§  173.]  What  are  the  characterizing  properties  of 
mercury  ? 

[§  174.]     What  peculiar  power  does  mercury  possess  ? 

How  is  this  property  of  mercury  taken  advantage  of?  What 
other  application  is  made  of  the  amalgams  of  gold  ?  What  ap- 
plication is  made  of  the  amalgam  of  silver  ?  For  what  partic- 
ular purpose  is  the  amalgam  of  tin  used  ? 

[§  175.]  In  how  many  different  proportions  does  mer- 
cury combine  with  oxygen  1  What  is  the  chemical 
composition  of  protoxide  of  mercury  ?  By  what  means 
is  it  obtained  1  What  is  the  composition  of  per-oxide  of 
mercury  ? 

[§  176.]     How  is  per-oxide  of  mercury  obtained  ? 

[^  177.]  In  how  many  proportions  does  mercury  com- 
bine with  Chlorine  ?  What  is  the  composition  of  proto- 
chloride  of  mercury  ?  By  what  name  is  this  compound 
generally  known  ? 

[§  178.]     How  is  calomel  obtained  ? 

[§  179.]  How  is  per-chloride  of  mercury  formed  ? 
How  is  corrosive  sublimate  prepared  for  medicinal  pur- 
poses ? 

[§  180.]  What  are  the  properties  of  corrosive  subli- 
mate ? 

[§  181.]  In  how  many  different  proportions  does  mer- 
cury unite  with  sulphur  ?  What  is  the  chemical  com- 
position of  proto-sulphuret  of  mercury  1  How  is  it  ob- 
tained ? 


OF    CHAPTER    III.  239 

[§  182.]  What  is  the  chemical  composition  of  bi-sul- 
phuret  of  mercury?  By  what  other  name  is  this  com- 
pound known  1  Is  it  a  product  of  nature  1  How  may  it 
be  produced  by  art?  For  what  purposes  is  it  employed  ? 

What  are  the  principal  binary  combinations  of  Mercury  ? 

[§  183.]  What  is  the  chemical  equivalent  of  silver  ? 
and  in  what  state  found  ?  Where  is  this  metal  principal- 
ly found?  What  are  its  properties?  With  what  sub- 
stance is  silver  generally  alloyed  ?  What  other  metal 
does  it  often  contain  in  minute  quantities?  For  what 
purposes  is  it  used  ? 

[§  184.]  With  what  substances  does  silver  combine? 
What  are  the  names  of  the  products  thus  formed  ? 

What  is  the  chemical  composition  of  oxide  of  silver  ? 

How  is  it  obtained  ? 

What  is  the  chemical  composition  of  chloride  of  silver  ? 
By  what  other  name  is  this  substance  known  ?  How 
is  it  formed  ?  What  are  its  properties  ? 

For  what  purposes  is  a  mixture  of  silver,  chalk,  and  pearl- 
ash  used  ? 

What  is  the  composition  of  sulphuret  of  silver  ?  Where 
does  this  compound  occur  ?  What  are  its  properties  ?  For 
what  is  it  used  ? 

WJiat  are  the  principal  binary  combinations  of  Silver  1 

185.]     What  is  the  chemical  equivalent  of  gold  ? 
n  what  state  is  gold  found?    Where  does  it  principally 
occur  ? 

What  are  its  properties  ?  By  what  mixture  of  acids  is 
gold  operated  upon  ?  What,  therefore,  has  this  mixture 
been  called  ? 

By  what  means  may  gold  be  revived  from  a  solution  in  ni- 
tro  muriatic  acid  ?  What  beautiful  experiment  may  on  this 
account  be  made  with  it?  For  what  purpose  is  the  etherial 
solution  of  gold  used  ?  How  is  it  prepared  ? 

[§  186.]  In  how  many  different  proportions  does  gold 
combine  with  oxygen  ?  With  what  other  substances  does 
it  yet  combine  ? 


240  RECAPITULATION 

What  are  the  principal  binary  combinations  of  Gold  ? 

[§  187.]  What  is  the  chemical  equivalent  of  platinum  ? 
Who  first  analyzed  the  ores  of  platinum  ?  What  other 
substances  (besides  platinum)  does  the  ore  of  platinum 
generally  contain  1  For  what  purposes  is  platinum  used 
in  Russia?  What  are  the  properties  of  platinum?  With 
what  substances  does  platinum  unite  ? 

For  what  two  purposes  is  platinum  used  in  chemistry  ?  In 
what  cases  is  it  well  adapted  to  the  manufacture  of  crucibles  ? 
How  is  the  flameless  or  aphlogistic  lamp  constructed  ?  (Ex- 
plain Fig.  CXIII).  How  is  this  phenomenon  explained  ? 

How  is  platinum-sponge  prepared  ?  How  does  hydrogen 
gas  act  upon  platinum-sponge  ?  Explain  Prof.  Dobereiner's 
apparatus  for  producing  instantaneous  light.  (Explain  Fig. 
CXIV). 

[§  188.]  What  is  the  chemical  equivalent  of  palladi- 
um ?  Where  does  it  occur  ?  With  what  other  substance 
is  it  found  combined  in  Brazil  1  What  are  its  properties  1 
By  what  acids  is  it  operated  upon  1  What  are  the  prop- 
erties of  sulphuret  of  palladium  ? 

[§  189.]     What  are  the  properties  of  rhodium  ? 
How  is  the  oxide  of  rhodium  obtained  ?     What  are  its 
properties  1 

[§  190.]  What  is  the  chemical  equivalent  of  iridium  ? 
Where  is  it  found  1  What  are  its  properties  ? 

[§  191.]  What  is  the  chemical  equivalent  of  osmium? 
How  is  this  metal  obtained  ?  What  are  its  properties  ? 

[§  192.]     What  is  the  equivalent  number  of  nickel  ? 

With  what  substances  is  nickel  generally  united  ?  By 
what  name  is  the  latter  of  these  combinations  known  in 
commerce  ?  What  are  the  properties  of  nickel  ?  How  is 
it  acted  upon  by  the  magnet  ?  Into  what  does  it  become 
converted  when  heated  ? 


OP    CHAPTER    III.  241 


D.     QUESTIONS  ON  THE  REMAINING  METALS,  IRON,  TIN, 

LEAD,  COPPER,  ZINC,  BISMUTH,  COBALT,  ANTIMONY, 

ARSENIC,  MANGANESE,  TELLURIUM,  TITANIUM, 

CERIUM,  URANIUM,  COLUMBIUM,  TUNGSTEN, 

CADMIUM,  CHROMIUM,  MOLYBDENUM, 

AND    VANADIUM. 

[§  193.]  What  is  the  chemical  equivalent  of  iron  ? 
In  what  state  is  iron  generally  found  ?  What  are  its 
properties. 

What  sort  of  ore  is  the  native  magnet  ?  In  what  state  does 
it  occur  ?  What  are  its  chemical  properties  ? 

[^  194.]  In  how  many  proportions  does  iron  combine 
with  oxygen  ?  What  is  the  chemical  equivalent  of  pro- 
toxide of  iron  1 

What,  that  of  the  per-oxide  of  iron  ? 

How  is  the  per-oxide  of  iron  obtained  ?  What  are  its 
properties  1  How  is  the  protoxide  obtained  ?  What  are 
its  properties  ?  How  is  the  black  oxide  of  iron  formed  ? 
What  sort  of  compound  is  it  1 

[$}  195.]  In  how  many  proportions  does  iron  combine 
with  chlorine  1  What  are  the  names  of  the  compounds  1 
What,  their  composition  1  How  is  proto-chloride  of  iron 
produced  ?  What  are  its  properties  ?  How  is  per-chlo- 
ride  of  iron  obtained  ?  What  are  its  properties  ? 

[§  196.]  What  sort  of  product  are  the  sulphurets  of 
iron  ?  By  what  name  is  the  bi-sulphuret  known  ?  Of 
what  color  is  it ;  and  in  what  state  is  it  found  ?  How  may 
the  proto-sulphuret  of  iron  be  produced  ? 

What  is  the  chemical  composition  of  proto-sulphuret  of 
iron  1  What,  that  of  the  bi-sulphuret? 

[§  197.]  In  what  manner  is  steel  formed?  What 
peculiar  properties  does  it  possess  in  a  higher  degree  thati 
iron?  What  process  must  steel  undergo  in  order  to  be- 
come adapted  to  the  different  uses  for  which  it  is  destined  ? 
In  what  does  the  process  of  tempering  consist? 

21 


242  RECAPITULATION 

What  are  the  principal  binary  combinations  of  iron  1 

[§  198.]     What  is  the  chemical  equivalent  of  lead  ? 
What  are  the  principal  properties  of  lead  ?     For  what 
purposes  is  it  extensively  used  ? 

[§  199.]  In  how  many  different  proportions  does  lead 
combine  with  oxygen  ?  What  are  the  names  of  the  pro- 
ducts ?  What  is  the  chemical  composition  of  the  sub-ox- 
ide of  lead  ?  What,  that  of  the  protoxide  ?  What,  that  of 
the  deutoxide  ?  What,  that  of  the  per-oxide  ? 

By  what  means  may  all  these  oxides  be  obtained  ?  What 
peculiar  property  do  they  possess?  For  what  purpose, 
therefore,  are  they  used  ? 

Explain  the  process  of  cupellation. 

How  is  the  protoxide  of  lead  (or  massicot  of  commerce)  ob- 
tained ?  What  is  this  substance  called  when  partially  melted  ? 

By  what  name  is  the  deutoxide  of  lead  known  in  commerce  ? 
What  are  its  properties  ? 

How  is  chloride  of  lead  produced  ?  What  are  its  prop- 
erties? What  is  its  chemical  composition  ? 

What  sort  of  product  is  the  sulphuret  of  lead  ?  What  kind 
of  ore  does  it  constitute  ? 

What  are  the  principal  binary  combinations  of  Lead  1 

[§  200.]  What  is  the  chemical  equivalent  of  tin  ?  To 
whom  was  this  metal  already  known  1  In  what  state  does 
it  commonly  occur  ?  What  are  its  properties  in  a  pure 
state  ? 

[§  201.]  In  how  many  different  proportions  does  tin 
combine  with  oxygen  1  WThat  is  the  chemical  composition 
of  the  protoxide  of  tin  1  What  that  of  the  per-oxide  ? 
How  may  both  products  be  obtained  ? 

What  becomes  of  tin,  when  fused,  and  in  this  state  for  a 
long  time  exposed  to  the  atmosphere  ?  What  becomes  of  the 
protoxide  when  again  exposed  to  heat  in  contact  with  air? 

What  are  the  properties  of  the  per-oxide  of  tin  ?  For 
what  purposes  are  the  oxides  of  tin  used  ? 

How  are  proto-chloride  and  per-chloride  of  tin  obtained  ? 
What  are  the  properties  of  the  proto-chloride  ?  What,  those 
of  the  per-chloride  ? 


or  CHAPTER  in.  243 

What  is  the  chemical  composition  of  proto-chloride  of  tin  ? 
What  is  the  chemical  composition  of  the  per-chloride? 

[§  202.]  How  are  the  two  sulphurets  of  tin  produced  ? 
What  are  their  properties? 

What  are  the  principal  binary  combinations  of  Tin  ? 

[§  203.]  What  is  the  chemical  equivalent  of  copper  ? 
How  long  is  it  since  this  metal  has  been  wrought  ?  In 
what  state  is  it  found  ?  With  what  substances  is  it  common- 
ly connected  ?  What  are  its  properties  ?  For  what  pur- 
poses is  it  used  ?  In  what  consists  one  of  its  chief  appli- 
cations ? 

[§  204.]  In  how  many  proportions  does  copper  com- 
bine with  oxygen  ?  Of  what  color  is  the  protoxide  ?  Of 
what  the  deutoxide  ?  What  is  the  chemical  composition  of 
these  substances  ? 

[§  205.]  How  is  proto-chloride  and  per-chloride  of 
copper  obtained  ?  What  are  the  properties  of  the  proto- 
chloride  ?  What  those  of  the  per-chloride  ?  What  prop- 
erty does  per-chloride  of  copper  communicate  to  spirits  of 
wine  in  which  it  is  dissolved  ? 

What  is  the  chemical  composition  of  proto-chloride  of 
copper  ?  What  is  the  chemical  composition  of  the  per- 
chloride  ? 

What  products  are  the  sulphurets  of  copper  ?  Where 
does  the  proto-sulphuret  of  copper  occur  ? 

What  are  the  most  important  binary  combinations  of 
Copper  ? 

[§  206.]     What  is   the  chemical  equivalent  of  zinc  ? 
In  what  state  is  zinc  found  ?     What  are  its  properties  ? 
How  is  zinc  acted  upon  by  heat  ? 

[§  207.]  How  are  the  oxides  and  chlorides  of  zinc 
formed  ? 

What  are  the  properties  of  the  oxide  of  zinc?  Wiiat 
those  of  chloride  ?  What  is  the  chemical  equivalent  of 
oxide  of  zinc  ?  What  that  of  the  chloride  ? 

[§  208.]     What  is  the  chemical  equivalent  of  bismuth? 


244  RECAPITULATION 

Where  does  this  metal  occur  ?  What  are  its  properties  ? 
For  what  purposes  is  it  used  ?  What  are  its  principal 
binary  combinations? 

[§  209.]  With  what  substances  is  cobalt  generally 
found  combined  ?  What  are  the  properties  of  pure  cobalt  1 
How  are  the  oxides  of  this  metal  obtained  ?  Under  what 
name  do  they  occur  in  commerce  ?  For  what  purposes  are 
they  used  ? 

[§  210.]  What  is  the  chemical  equivalent  of  antimony  ? 
Where  does  it  occur  1  What  are  its  properties  ?  For 
what  purposes  is  it  used  1 

[§  211.]  In  how  many  different  proportions  does 
antimony  combine  with  oxygen  ?  What  is  the  chemical 
composition  of  the  protoxide  ?  How  may  it  be  obtained  ? 
What  are  its  properties^ 

How  may  the  deutoxide  be  obtained?  What  are  its 
properties?  What  is  the  chemical  composition  ofper-ox- 
ide  of  antimony  ?  By  what  means  is  it  formed  ?  What 
are  its  properties  7 

How  is  the  Proto-chloride  or  butter  of  antimony  obtained  ? 
What  are  its  properties  ?  With  what  other  substances  does 
cobalt  yet  combine  ? 

What  are  the  principal  binary  combinations  of  Anti- 
mony 1 

[<§,  212.]  What  is  the  chemical  equivalent  of  arsenic  ? 
By  whom  was  arsenic  first  obtained  ?  Where  does  it  oc- 
cur ?  What  are  its  properties  ? 

[§  213.]  In  how  many  proportions  does  arsenic  com- 
bine with  oxygen  1  What  sort  of  compound  is  oxide  of 
arsenic  ?  What  are  its  properties  ?  What  is  the  chem- 
ical composition  of  arsenious  acid  ?  What  are  its  proper- 
ties ?  For  what  purposes  may  it  be  used  ? 

What  is  the  composition  of  arsenic  acid  ? 

Where  does  it  occur  ?     How  may  it  be  obtained  by  art  ? 

[§  214.]  What  is  a  combination  of  arsenic  with  hy- 
drogen called  ?  What  are  its  properties  ? 


OF    CHAPTER    III.  245 

Under  what  name  does  the  sulphuret  of  arsenic  occur 
in  commerce  1  For  what  is  it  used  ? 

What  are  the  principal  binary  combinations  of  Arsenic  1 

[§  215.]  What  is  the  chemical  equivalent  of  manga- 
nese ?  Where  does  manganese  occur  ?  What  are  its 
properties  ? 

[§  216.]  In  how  many  proportions  does  manganese 
combine  with  oxygen  ?  For  what  purposes  is  the  per-oxide 
used  ?  Where  does  the  chloride  of  manganese  occur  ? 

What  are  the  principal  combinations  of  manganese  ? 

[§  217.]  What  is  the  chemical  equivalent  of  telluri- 
um ?  Where  does  this  metal  occur  ?  What  peculiar 
property  has  it,  among  the  metals  ? 

[§  218.]  In  what  state  does  titanium  occur?  What 
are  its  properties  ? 

[§  219.]  What  is  the  chemical  equivalent  of  cerium  ? 
Where  does  it  occur  1  What  are  its  properties  ? 

[§  220.]  How  is  Uranium  obtHned  ?  What  are  its 
properties  1  In  how  many  proportions  does  it  combine 
with  oxygen  ? 

[§  221.]  What  is  the  chemical  equivalent  of  columbi- 
um  1  By  whom  was  it  discovered  ?  In  what  ?  What 
are  its  properties  1  In  how  many  proportions  does  it  com- 
bine with  oxygen  ? 

[§  222.]  What  is  the  chemical  equivalent  of  tungsten  ? 
Where  does  it  occur  ?  What  are  its  properties  ?  In  how 
many  different  proportions  does  it  combine  with  oxygen  ? 

[§  223.]  What  is  the  equivalent  number  of  cadmium  ? 
By  what  means  is  this  metal  obtained?  What  metal  does 
it  resemble  in  color  and  properties  ?  What  are  its  other 
properties  ?  What  combination  of  this  metal  has  lately 
been  employed  in  oil-painting  ? 

[§  224.]    What  is  the  chemical  equivalent  of  chromium  ? 
21* 


246  RECAPITULATION. 

In  what  state  is  this  metal  found  ?  What  are  its  proper- 
ties 1  In  how  many  different  proportions  does  it  combine 
with  oxygen  1  How  may  the  protoxide  be  obtained  ? 
What  are  its  properties  ?  How  is  the  deutoxide  produced  ? 
What  are  its  properties  ?  What  sort  of  product  is  chro- 
mic acid  1  What  are  its  properties? 

[§  225.]  Where  does  molybdenum  occur  1  How  is 
it  obtained  ?  What  are  its  properties  ? 

[§  226.]  By  whom  was  vanadium  first  discovered  1 
Where  has  it  been  found  ?  What  are  its  properties  ?  In 
how  many  proportions  does  it  combine  with  oxygen  ? 


OF    THE    SALTS.  247 


CHAPTER    I  V. 


OF    THE     Q,UARTERNARY    COMBINATIONS    OF      BODIES,    OR 

SALTS, 


General  Remarks  on  the  Acids. 

§  227.  The  general  characteristics  of  those  binary 
compounds  (combination  of  one  element  with  another) 
called  acids,  have  already  been  enumerated  in  the  intro- 
duction, page  38.  It  will  be  well  now  to  draw  a  few  gen- 
eral inferences  from  the  properties  of  these  substances,  as 
far  as  we  have  become  acquainted  with  them  in  the  three 
preceding  chapters. 

Among  the  different  elements,  oxygen  and  hydrogen 
are  by  far  the  most  powerful  agents  in  nature.  They 
enter  into  almost  every  composition  of  organic  or  inor- 
ganized  matter  ;  and  although  marked  by  the  most  dis- 
tinguishing properties  which  can  possibly  designate  two 
heterogeneous  bodies,  the  product  of  their  union — water  — 
is  the  most  indifferent  (neutral)  substance  known  ;  and  so 
perfect  and  compact  is  this  compound,  that  it  occupies 
less  than  one  two  thousandth  part  of  the  volume  which  its 
two  constituent  gases  (hydrogen  and  oxygen)  occupy  be- 
fore their  combination  (Chap.  I,  §  27).  But  although  oxy- 
gen and  hydrogen  are  capable  of  thus  neutralizing  each 
oilier,  their  relation  to  other  substances  is  quite  different. 
For  it  may  be  said  that  all  bodies,  in  relation  to  these  two 
are  merely  passive,  and  receive  as  it  were  their  character- 
izing properties  from  the  proportion  in  which  they  combine 
with  either  oxygen  or  hydrogen. 


248  GENERAL    REMARKS 

As  an  instance  we  may  take  the  different  properties  of  the 
combinations  of  nitrogen  with  oxygen  (see  Chap.  I,  §  46,) 
which  seem  solely  to  depend  on  the  proportion  in  which  the 
latter  substance  combines  with  the  former.  And  so  entirely 
are  the  original  characteristics  of  nitrogen  changed  by  its 
union  with  oxygen,  that  4  volumes  of  it,  mixed  with  1  volume 
of  oxygen,  form  a  respirable  gas,  eminently  calculated  to  sup- 
port animal  life,  while  a  combination  of  one  volume  of  nitro- 
gen with  five  volumes  of  oxygen,  constitutes  a  body  in  the 
highest  degree  destructive  to  all  organic  formation. 

§  228.  The  most  remarkable  products  obtained  by  the 
combination  of  oxygen  and  hydrogen  with  other  substan- 
ces, are  the  acids.  The  body  which  in  combination  with 
oxygen  or  hydrogen  forms  an  acid,  is  called  the  radical, 
and  the  oxygen  or  hydrogen  with  which  it  unites  is  termed 
the  acidifying  principle.  Thus,  in  nitric  acid  (see  §  56), 
oxygen  is  the  acidifying  principle ;  but  in  muriatic  acid 
and  prussic  acid  it  is  hydrogen. 

It  is  here  important  to  observe  that  every  acid  may  be  con- 
sidered as  the  union  of  an  electro-positive  with  an  electro  nega- 
tive body*  ;  the  radical  being  always  the  electro-positive,  and 
the  acidifying  principle  the  electro-negative  factor. 

It  was  formerly  believed  that  oxygen  was  the  acidifying 
ingredient  of  every  acid,  but  the  discovery  of  the  acidifying 
qualities  of  hydrogen  has  sufficiently  corrected  that  error. 
(Compare  the  note  at  the  bottom  of  this  page). 

*  The  ancient  divisions  of  bodies  into  acidifying  substances  or  sup- 
porters of  combustion,  and  such  as  are  capable  of  being  acidified  or 
burnt  (combustibles),  is  vague  and  no  longer  applicable.  For  it 
has  been  proved  tbat  one  and  the  same  substance  may  in  one  instance 
be  capable  of  combustion  with  oxygen,  and  in  another  be  the  acid- 
ifying principle  in  combination  with  a  different  substance. 

To  give  an  example  :  Hydrogen  combines  with  oxygen  to  com- 
bustion, the  product  being  water  (see  Chap.  I,  §  23),  while  on  the 
other  hand  it  communicates  the  acid  qualities  to  muriatic,  iodic,  and 
fluoric  acid  (§  67,  §  124,  §  133).  Thus,  hydrogen  would  belong 
to  both  the  combustible  and  the  acidifying  substances.  There  are, 
moreover,  but  few  substances,  besides  oxygen,  capable  of  supporting 
combustion  (only  a  small  number  of  bodies  burn  in  chlorine,  iodine, 
and  fluorine).  All  ordinary  processes  of  combustion  result  from  a 
combination  of  oxygen  with  a  combustible  basis;  and  most  acids  are 
supporters  of  combustion  only  by  virtue  of  the  greater  or  less  quantity 
of  oxygen  which  enters  into  their  composition. 


ON    THE    SALTS.  249 

J  229.  Those  acids  in  which  hydrogen  enters  as  the 
acidifying  principle,  are  called  hydro  adds.  To  these 
belong 

The  Muriatic  add,  composed  of  chlorine  and  hydrogen 
(see  Chap.  I,  §  67). 

The  Hydro-bromic  add,  composed  of  bromine  and  hy- 
drogen (see  Chap.  II,  §  129). 

The  Hidriutic  add,  composed  of  iodine  and  hydrogen 
(see  Chap.  II,  §  125). 

The  Hydro-fluoric  add,  composed  of  fluorine  and  hy- 
drogen (see  Chap.  II,  §  134). 

The  Sulphureted  hydrogen,  composed  of  sulphur  and 
hydrogen  (see  Chap.  II,  §  106). 

The  Hydro-cyanic,  or  prussic  acid,  composed  of  cyano- 
gen and  hydrogen  (see  Chap.  II,  §  90). 

Many  other  acids,  however,  require  water  (consequent- 
ly also  hydrogen,  which  is  an  ingredient  of  water)  for  their 
solid  or  liquid  form.  These  acids  are  termed  hydrates, 
and  have  likewise  the  word  '  hydro'  prefixed  to  their 
names.  Thus,  we  speak  of  hydro-nitric  acid,  hydro-sul- 
phuric acid,  &/c.  Those  acids  in  which  water  does  not 
enter  as  an  essential  ingredient  are  called  an-hydrous, 
(Compare  the  remark  §  58,  page  99). 

§  230.  The  acids  combined  with  those  substances 
called  bases  (see  Intro,  page  38)  form  a  new  class  of  bodies 
designated  by  the  name  of  salts.  A  salt,  therefore,  is 
a  combination  of  a  basis  with  an  acid. 

When  a  salt  is  again  decomposed  by  the  almost  univer- 
sal agency  of  galvanic  electricity,  the  acid  adheres  inva- 
riably to  the  positive  pole,  while  the  basis  is  attracted  by 
the  negative  pole  of  the  battery.  Hence  from  the  law  of 
electricity  we  may  infer  that  the  acids  are  electro -negative, 
and  the  bases  electro-positive  substances. 

This  is  a  remark  we  have  already  had  occasion  to  make  in 
the  Introduction,  pages  38  and  39,  where  we  have  stated  that 
galvanic  electricity  is  by  far  the  best  criterion  of  an  acid  or  a 
basis.  Neither  the  sour  taste  nor  the  changing  of  vegetable 
colors  can  be  relied  upon  as  infallible  characteristics. 

We  have  already  stated  in  the  Introduction  that  some  chem- 
ists of  distinction,  at  the  suggestion  of  Sir  Humphrey  Davy,  are 


250  GENERAL,    REMARKS 

inclined  to  believe  that  all  chemical  phenomena  are  the  result 
of  electrical  attractions,  either  in  the  same  or  in  opposite  di- 
rections. This  theory  has  lately  been  supported  by  some  of 
the  most  distinguished  English  chemists,  and  is  indeed  so 
strongly  corroborated  by  facts  that  it  must  at  least  be  consid- 
ered an  ingenious  hypothesis,  which  in  course  of  time  may 
perhaps  arrive  at  greater  perfection.  We  will  now  only  men- 
tion a  few  facts  attending  the  decomposition  of  salts  by  galvanic 
electricity,  which  are  in  themselves  highly  interesting,  and 
may  serve  to  explain  why  the  bases  are  called  electro-posi- 
tive, and  the  acids  electro-negative  bodies. 

Fig.  CXV. 


EXPERIMENT  I.  When  a  solution  of  a  salt  is  made  in  water, 
and  placed  in  two  cups,  a  and  6,  of  which  one  is  connected 
with  the  positive  or  zinc  pole,  and  the  other  with  the  negative 
or  copper  pole  of  a  galvanic  battery,  and  a  communication  is 
established  between  the  two  cups  by  a  wet  conductor  (which 
may  be  a  piece  of  cotton  or  some  other  moistened  substance) ; 
then  after  the  battery  has  been  for  some  time  in  motion,  the 
acid  of  which  the  salt  is  composed  will  pass  into  the  cup  con- 
nected with  the  positive  or  zinc  pole  and  the  basis  will  be  trans- 
ferred to  the  cup  which  is  connected  with  the  negative,  or  cop- 
per pole —  so  that  after  sometime  the  solution  in  the  cup 
a,  will  have  acquired  a  sour  taste,  and  that  in  the  cup  6, 
will  taste  alkaline. 

Now  this  phenomenon  is  easily  accounted  for  by  the  electric 
attraction  of  the  battery.  The  salt  which,  as  we  have  said,  is 
always  a  compound  of  an  acid  with  a  basis,  is  by  the  opposite 
electric  attraction  of  the  battery  decomposed  into  its  two  con- 
stituent principles  ;  because  the  positive  pole  of  the  battery  at- 
tracts the  acid,  and  the  negative  pole  the  basis,  more  strongly 
than  these  substances  attract  each  other;  their combinatory  at- 
traction therefore  is  overcome  or  destroyed,  which  enables  each 
of  them  to  follow  the  impulse  received  by  the  attractive  force  of 
electricity,  and  it  is  on  this  account,  the  acid,  which  is  the  elec- 


ON    THE    SALTS.  251 

tro-negative  substance,  collects  (by  the  law  of  opposite  at- 
traction, Natural  Philosophy,  Chap.  X)  in  the  cup  near  the 
negative  pole,  and  the  alkali,  or  basis,  passes  over  into  the  cup 
connected  with  the  positive  pole,  because  it  is  an  electro-neg- 
ative body. 

A  still  more  striking  instance,  showing  the  decomposing 
power  of  galvanic  electricity,  is  the  following 

EXPERIMENT  II.    Place  a  saline  solution  in  the  middle  cup  d, 

Fig.  CXVI. 


and  pure  water  in  the  two  cups  c  and  e.  Connect  the  water  in 
the  cups  c  and  e,  respectively  with  the  positive  and  negative 
poles  of  the  battery,  and  establish  a  direct  communication  be- 
tween the  three  cups  c,  rf,  e,  as  in  the  last  experiment,  by  means 
of  some  wet  conductor.  After  the  battery  has  for  some  time 
been  in  motion,  the  saline  solution  contained  in  the  cup  d,  will 
not  only  be  decomposed,  but  will  absolutely  have  disappeared 
from  this  cup  —  the  acid  being  transferred  to  the  cup  c,  con- 
nected with  the  positive  pole,  and  the  alkaline  basis  to  the  cup 
e,  connected  with  the  negative  pole  of  the  battery,  while  the 
liquid  in  the  cup  d,  will  have  acquired  a  pure  taste,  like  water. 

We  see  from  this  expperimcnt  that  the  attractive  force  of 
galvanic  electricity  has  not  only  the  power  of  decomposing  a 
saline  solution,  but  is  actually  capable  of  acting  through  the 
medium  of  another  substance.  But  what  is  still  more  sur- 
prising, it  is  even  capable  of  suspending  the  laws  of  affinity 
which  one  body  has  for  another,  as  is  proved  by  the  following 
fact. 

If  in  the  last  experiment  a  solution  of  sulphate  of  soda 
is  put  in  the  cup  connected  with  the  negative  or  copper 
pole,  and  in  the  other  two  an  infuson  of  red  cabbage,  (which  is 
a  strong  test  of  the  presence  of  an  acid,  because  most  acids 


252  GENERAL    REMARKS 

change  its  color),  then  after  the  galvanic  battery  has  been  for 
some  time  in  motion,  the  sulphate  of  soda  becomes  decom- 
posed, and  the  sulphuric  acid  of  which  it  is  composed  is  trans- 
ferred to  the  cup  which  is  connected  with  the  positive  pole  of 
the  battery,  without  changing  in  the  least  degree  the  color  of 
the  infusion  in  the  middle  cup,  through  which  it  is  obliged  to 
pass.  If  the  middle  cup  is  filled  with  an  alkaline  solution,  the 
acid  is  still  transferred  to  the  positive  pole  of  the  battery,  with- 
out combining  in  the  least  with  it,  and  in  the  same  manner 
may  an  alkaline  solution  be  transferred  through  an  acid. 

Now  these  experiments,  if  they  are  not  sufficient  to  prove 
beyond  a  doubt  the  correctness  of  the  electro-chemical  theory, 
given  in  the  introduction,  justify  at  least  what  we  have  said 
in  reference  to  the  criterion  of  an  acid  and  a  basis  —  and  the 
classification  of  bodies  into  electro-positive  and  electro-negative 
substances. 

§  231.  The  bases,  or,  as  they  are  sometimes  called,  the 
salijiable  bases,  with  which  the  acids  combine,  are,  with  the 
exception  of  ammonia  (Chap.  I,  §  61),  all  OXIDES,  or  at 
least  combinations  of  oxygen.  Both  inorganic  arid  organ- 
ic bodies  are  capable  of  being  salifiable  bases,  that  is,  or 
to  combine  with  the  acids  to  salts. 

They  are  therefore  divided  into 

I.     BASES  FROM  THE  MINERAL  KINGDOM. 

A.   SOLUBLE  IN  WATER.  B.    INSOLUBLE  IN  WATER. 

a.  Easily  soluble,     b.  Not  easily     a.  Earths,     b.  The  remaining 

Soluble.  METALLIC 

Potash,  Baryta,  Alumine,  bases. 

Soda,  Strontia,          Berillia, 

Lythia,  Lime,  Yttria, 

Ammonia,  Magnesia,       Zirconia, 

Thoria. 

II.     ORGANIC  BASES. 

A.     VEGETABLE  BASES.  B.     ANIMAL  BASES. 

The  different  properties  of  these  bases,  with  the  exception 
of  those  from  the  animal  arid  vegetable  kingdoms  (which  will 


ON    THE    SALTS.  253 

be  treated  of  in  animal  and  vegetable  chemistry,  (see  Chapters 
V,  and  VI),  have  already  been  described  in  the  preceding 
sections. 

REMARK.  Since  all  the  bases  here  enumerated  are  al- 
ready binary  combinations  of  an  element  with  oxygen,  and 
the  acids  with  which  they  combine  are  likewise  composed 
of  two  principles,  it  follows  that  we  may  consider  a  salt  as 
a  combination  of  two  binary  compounds  —  or,  which  is 
the  same,  as  a  Quarternary  compound. 

Nomenclature  of  Salts. 

§  232.  Each  of  the  acids  we  have  become  acquainted 
with  in  the  preceding  chapter,  is  capable  of  uniting  with 
all  the  bases  just  enumerated  ;  each,  therefore,  forms  a 
distinct  class  of  salts,  which  is  generally  denominated  after 
the  acid  which  enters  into  its  composition.  The  way  in 
which  this  is  done  is  easily  understood  :  The  termination 
of  the  acid  ending  in  ic  is  changed  into  ate ;  that  which 
ends  in  ous  into  ite ;  to  which  is  added  the  name  of  the 
base,  in  the  genitive  case.  Thus,  the  salts  which  are  form- 
ed by  the  combination  of  sulphun'c  acid  with  the  different 
salifiable  bases,  are  called  sulphates ;  those  in  which  sul- 
phuroMs  acid  is  an  ingredient  are  called  sulphas ;  and  so 
of  the  rest.  Now  if,  for  example,  we  wished  to  denote  the 
salt  arising  from  the  combination  of  sulphune  acid  with 
soda,  we  should  call  it  sulphate  of  soda;  if  we  wished  to 
denote  the  salt  in  which  sulphurous  acid  is  united  with 
ammonia,  we  say  sulphzfe  of  ammonia,  &c. 

This  nomenclature  of  the  salts  is  of  immense  advantage  to 
the  memory,  and  infinitely  preferable  to  the  arbitrary  names 
by  which  they  were  formerly  designated.  Thus,  instead  of 
Glauber's  salts,  butter  of  antimony,  &.c,  we  say  now  sulphate  of 
soda,  muriate  of  antimony,  &c,  by  which  appellations  we  can- 
not but  recollect  their  constituent  principles,  viz. :  sulphuric 
acid  and  soda,  muriatic  acid  and  antimony,  &c. 

It  will  therefore  be  unnecessary  to  describe  the  elementary 
ingredients  of  the  salts,  as  their  appellations  sufficiently  indi- 
cate their  composition. 

Neutral,   sour,   and  basic  Salts. 

§  233.     The  salts  have  yet  been  divided  into   neutral, 
sour,  and  basic  salts.     By  a  neutral  salt  is  meant  one  in 
22 


254  CRYSTAL  OGKAPHY'. 

which  the  properties  of  the  acid  and  the  base  of  which  it 
consists  are  neutralized  ;  sour  are  those  salts  in  which  the 
acid  properties  are  prevalent ;  and  basic  those  in  which  the 
properties  of  the  basis  are  yet  distinguishable. 

Decrepitation  of  salts. 

§  234.  All  salts  which  are  obtained  from  crystals,  con- 
tain a  certain  proportion  of  water  either  mechanically  en- 
tangled —  in  which  case  it  is  called  water  of  cry stalization 
—  or  chemically  combined  —  as  an  essential  principle  to 
their  formation.  Those  which  contain  water  mechanically 
entangled,  easily  decrepitate,  that  is,  fly  off  in  small  par- 
ticles when  thrown  into  fire.  This  is  owing  to  the  expan- 
sion of  steam,  into  which  their  water  of  crystalization  is 
converted  by  exposure  to  heat.  Those  salts  in  which  wa- 
ter is  a  chemical  constituent  hardly  ever  decrepitate. 

Phenomena  of  efflorescence  and  deliquescence. 

§  235.  Some  salts  lose  their  water  either  at  common 
temperatures  of  the  atmosphere,  in  which  case  they  become 
a  shapeless  powder,  and  are  said  to  effloresce,  or  they  absorb 
moisture  from  the  atmosphere,  and  melt,  which  process  is 
called  that  of  deliquescence.  But  there  are  others  which  may 
be  melted  in  a  strong  heat,  without  being  decomposed  ;  and 
there  are  salts  which  melt  in  their  own  water,  when  its  solv- 
ing power  is  increased  by  heat.  The  first  process  is  called 
igneous  fusion ;  the  second  is  termed  aqueous  fusion. 

Crystalography . 

Before  entering  on  the  description  of  the  chemical  proper- 
ties of  salts,  we  must  here  mention  some  highly  interesting 
peculiarities  in  their  chemical  conformations  which  were  first 
noticed  by  Haiiy,  a  celebrated  French  philosopher,  and  have 
since  occupied  much  of  the  time  and  researches  of  many  dis- 
tinguished chemists. 

We  have  already  stated  (in  the  first  chapter  of  Nat.  Phil.) 
that  whenever  a  body  passes  from  the  liquid  to  the  solid  state, 
or,  in  other  words,  whenever  a  body  from  a  state  of  solution  is 
converted  into  a  solid,  so  that  its  particles  are  capable  of  fol- 
lowing their  own  mutual  attractions,  they  arrange  themselves 
in' regular  mathematical  forms,  in  which  state  they  are  called 
crystals.  These  crystals  are  of  various  shapes,  according  to 


CRYSTALOGRAPHY. 


255 


the  different  substances  of  which  they  are  formed,  and  it  even 
happens  that  the  crystals  of  one  and  the  same  substance  are 
capable  of  assuming  different  geometrical  forms.  Now  it 
was  reserved  for  Haiiy  first  to  show  by  a  series  of  the  most 
beautiful  experiments,  that  all  crystals  are  more  easily  divided 
in  certain  directions  than  in  others,  so  that  if  a  portion  be  cut 
off  in  one  of  these  directions,  the  surface  will  be  perfectly 
smooth  and  regular,  whereas,  in  every  other  direction  we  ob- 
tain a  rough  surface  or  a  common  fracture.  By  continuing  the 
division  of  a  crystal,  following  always  the  direction  in  which 
it  is  most  readily  divided,  and  presents  a  regular,  smooth  sur- 
face, Haiiy  finally  arrived  at  certain  geometrical  forms,  which 
were  then  no  longer  divisible  without  fracture.  This  geomet- 
rical form,  which  is,  as  it  were,  the  nucleus  of  the  crystal,  he 
called  the  primitive  form  of  the  crystal,  and  the  shape  which  it 
had  before  the  division  he  called  the  secondary  form. 

By  a  long  and  painful  investigation  of  a  great  variety  of 
crystals  he  found  that  their  primitive  forms  were  all  reducible 
to  six  regular,  geometrical  solids,  which  are, 

1st.    The    parallelepiped,    which   form    includes  the    cube 

Fig.  CXVII.         Fig.  CXVIII.  Fig.  CXIX. 


(Fig.  CXVII),  the  four-sided  prism  (Fig.  CXVIII),  and  the 
rhomboid  —  three  solids  which  are  bounded  by  six  quadrilateral 
faces. 

2d.  The  tedrahedron,  of  which  three  different  views  are  given 
Fig.  CXX. 


in  Fig.  CXX,  and  which  is  bounded  by  four  triangular  surfaces 


256 


CRYSTALOGRAPHY. 


3d.  The  octahedron,  of  which  two  differest  views  (in  outline, 
and  shaded)  are  given  in  Fig.  CXXI,  bounded  by  eight  trian- 
gular sides,  or  which  may  also  be  conceived  as  formed  by  join- 
ing the  bases  of  two  triangular  pyramids. 

Fig.  CXXI.  Fig.  CXXII. 


4th.  The  six-sided  prism,  represented  in  Fig.  CXII,  bound- 
ed by  six  parallelograms,  and  two  parallel  bases. 

5th.  The  rhombic  dodecahedron,  represented  in  Fig.  CXXIII, 
bounded  by  twelve  rhomboidical  surfaces,  and 

Fig.   CXXIII.  Fig.   CXXIV. 

r 


6th.  The  dodecahedron,  represented  in  Fig.  CXXIV,  which 
is  a  solid,  bounded  by  twelve  triangles,  and  which  may  be 
conceived  to  be  formed  by  the  junction  of  the  bases  of  two  six- 
sided  pyramids. 

These  six  forms  being  not  so  simple  as  we  might  expect  from 
a  pure  mathematical  investigation  of  their  formation,  it  is  high- 
ly probable  that  the  more  complicated  of  them  are  themselves 
composed  of  the  more  simple  ones,  which,  according  to  the 
Fig.  CXXV.  Fig.  CXXVI.  Fig.  CXXVII. 


CRYSTALOGRAPHY. 


257 


opinion  of  some  philosophers,  are  the  tedahedron  (Fig.  CXXV), 
the  triangular  prism  (Fig.  CXXVI),and  the  parallelepiped  (Fig. 
CXVll),  because  it  may  be  proved  mathematically  that  the  six 
primitive  forms  may  be  produced  by  a  proper  combination  of 
these  three.  On  this  account  the  three  solids  which  we  have  just 
named,  are  called  integrant  molecules,  because  they  are  con- 
ceived to  be  the  constituent  geometrical  forms  from  which  the 
secondary  shape  and  even  the  primitive  forms  of  all  crystals 
are  derived. 

As  an  example  we  will  only  mention  the  six-sided  prism, 
or  in  fact  any  prism  whatever,  which  may  evidently  be  divided 
into  as  many  triangular  prisms  as  it  has  sides,  by  drawing  from 
all  the  corners  straight  lines  to  the  centre  of  the  bases  and 
passing  planes  in  the  direction  of  these  lines  ;  and  the  rhombic 
dodecahedron,  which  it  is  easily  perceived  may  be  formed  by 


Fig.  CXXVIII. 


integrant  cubes,  as  rep- 
resented in  the  figure, 
by  placing  rows  of  them 
upon  all  the  sides  of  the 
cubical  nucleus,  making 
each  row  recede  one 
step  further,  until  reg- 
ular pyramids  are  form- 
ed, of  which  two  and 
two  form  a  rhombical 
surface.  (This  is  shown 
in  the  figure,  which  is 
taken  from  Hauy's  Phi- 
losophy, plate  II,  fig. 
12.)  Three  sides  of  the 
cubic  nucleus  are  pur- 
posely left  remaining  to 
exhibit  the  gradual  for- 
mation of  a  rhombic  surface  upon  two  contiguous  sides. 

This  theory,  however  ingenious,  does  not  quite  satisfy  the  de- 
mands of  strict  mathematical  reasoning.  The  secondary  form  of 
some  crystals,  particularly,  cannot  very  well  be  accounted  for  on 
the  supposition  that  they  are  formed  by  the  piling  upon  one  an- 
other of  the  integrant  molecules,  although  the  objections  made 
against  it  by  some  philosophers,  that  the  molecules  would  in 
this  case  have  spaces  between  them,  can  be  but  of  little  avail; 
because  there  is  no  geometrical  figure  that  the  molecules 
could  possibly  assume,  which  would  not  be  more  or  less  ob- 
jectionable on  this  account.  To  wave  these  objections,  Dr 
Wollaston,  one  of  the  most  ingenious  philosophers  of  the 
22* 


258 


GENERAL   REMARKS. 


present  age,  has  improved  the  theory  of  integrant  molecules, 
by  showing  the  possibility  of  constructing  both,  the  primitive 
and  secondary  forms  of  crystals,  by  means  of  small  integrant 
spheres,  as  may  be  seen  from  the  adjoining  figures. 


Fig.  CXXIX.          Fig.  CXXX. 


Fig.  CXXXI. 


Fig.  CXXXII.       Fig.  CXXXIII.      Fig.  CXXXIV. 


He  supposes  the  intergant  molecules  of  crystals  to  be 
spheres,  and  the  six  primitive  and  all  secondary  forms  of 
bodies,  produced  by  the  piling  upon  one  another  of  these 
spheres.  This  theory  is  in  many  respects  superior  to  Hauy's, 
and  although,  as  yet,  far  from  being  satisfactorily  demonstra- 
ted, deserves  to  be  preferred  to  Hauy's  for  the  following 
reasons: 

1.  On  account  of  its  greater  simplicity  (adopting  but  one 
from  for  all  integrant  molecules). 

2.  Because  it  seems  to  agree  better  with  the  general  laws 
of  nature — the  spherical  form  being  the  most  perfect  of  all, 
containing  (as  may  be  proved  mathematically)  the   greatest 
quantity  of  matter,  or  space,  bounded  by  the  smallest  surface  ; 
and  it  being  the  form  which  all  bodies  in  nature  spontaneously 
assume,  when  solely  acted  upon  by  the  cohesive  attraction  of 
their  particles. 

3.  Because  all  crystals  are  formed  by  bodies  passing  spon- 
taneously from  the  liquid  into  the  solid  state  ;  and  it  is  therefore 
highly  probable  that  the  particles  will  adopt  that  arrangement 
which  is  most  natural.     Moreover,  it  can  be  proved  geometric- 
ally, that    if  they  are   solely  impelled  by   their  gravitation 
towards  each    other,  they   must    arrange  themselves    round 


NITRATES.  259 

their  common  centre  of  gravity,  and  consequently  form 
spheres. 

Whichever  theory  we  adopt,  we  must  not  forget  that  it  is 
but  an  ingenious  hypothesis,  which,  although  serving  our  im- 
agination, is  as  yet  far  from  being  established  by  actual 
experiment ;  and  it  is  more  than  probable  that  we  shall  never 
be  able  to  lift  the  veil  with  which  nature  covers  all  her  works. 
We  can  only  worship  and  wonder  at  the  simplicity  of  the 
means  which  she  adopts  to  produce  the  greatest  ends  ;  but  of 
her  secret  operations  we  know  nothing,  either  in  this  or  any 
other  of  the  natural  sciences. 

We  shall  now  proceed  to  describe  the  composition  and  prin- 
cipal properties  of  those  salts  which  are  useful  in  common  life, 
and  of  some  application  in  the  arts.  A  comprehensive  treatise 
on  this  subject  would  fill  volumes,  and  far  exceed  the  limits 
proposed  in  a  work  of  an  elementary  nature. 

§  236.  The  principal  salts  obtained  from  the  combi- 
nation of  the  acids  with  the  different  salifiable  bases,  are, 
according  to  the  nomenclature,  explained  in  §  232,  the 
Nitrates,  Chlorates,  Chlorides,  Muriates  (chlorides),  Sul- 
phates, Carbonates,  Phosphatest  Chromates,  Arseniates, 
Cyannites,  and  fulminates. 


A.     NITRATES. 

§  237.  Properties  of  the  Nitrates.  The  combinations 
of  nitric  acid  with  the  various  salifiable  bases  gives  rise  to 
a  class  of  salts  extensively  used  in  the  arts.  The  general 
properties  by  which  they  are  distinguishable  as  a  class,  are 
the  following  : 

1.  They  are  all  decomposed  by  heat. 

2.  They  are  acted  upon  by  all  simple  combustible  sub- 
stances. 

3.  They  decompose  the  fixed  acids. 

4.  They  are  soluble  in  water. 


260  NITRATE    OF    POTASH. 


1.     Nitrate  of  Potash  (Nitre,  Saltpetre). 

Chemical  Composition  :      I  equiv.  of  nitric  acid  =    54 
1  equiv.  of  oxide  of  potassium,  or  potash  =    48 


Consequently,  chem.  equiv.  of  nitrate  of  potash  =  102. 

<§  238.  This  salt  occurs  in  nature  in  the  mineral  and 
vegetable  kingdoms.  It  collects  on  damp  walls,  in  sub- 
terraneous places,  in  cellars,  dirty  lanes,  and  wherever 
lime,  potash,  or  decayed  animal  substances  abound.  It 
is  also  obtained  by  neutralizing  nitric  acid  with  potash. 

The  nitre  which  occurs  in  commerce  and  which  is  used  in 
the  manufacture  of  gunpowder,  is  obtained  by  throwing  in  heaps 
the  remains  of  decayed  vegetable  matter.  Nitric  acid  is 
by  this  means  spontaneously  generated  by  the  decomposition 
of  these  substances,  which  as  we  shall  see  hereafter,  are 
principally  composed  of  nitrogen.  Such  heaps  are  called 
nitre-beds.  They  must  from  time  to  time  be  sprinkled  with 
water,  when  after  remaining  in  this  state  for  several  months, 
nitre  will  be  formed,  in  combination  with  nitrate  of  lime 
and  of  magnesia.  From  these,  and  the  earth  with  which  it  is 
mixed,  it  is  freed  by  dissolving  it  in  water,  and  adding  to  the 
solution  a  small  quantity  of  potash,  which  decomposes  the  ni- 
trates of  lime  and  magnesia,  and  leaves  the  nitrate  of  potash 
pure.  The  solution  is  afterwards  evaporated  and  the  nitre 
obtained  in  crystals. 

This  mode  of  treating  nitre  is  much  resorted  to  in  France 
and  particularly  in  Germany,  for  the  manufacture  of  gunpow- 
der ;  but  in  England  and  this  country  nitre  is  imported  from 
the  East  Indies,  where  it  is  found  already  formed  in  a  state  of 
efflorescence,  particularly  after  heavy  rains. 

§  239.  Properties  of  Nitre.  It  has  a  bitter  (somewhat 
sour,)  cooling  taste,  is  perfectly  inodorous,  becomes  liquid 
by  igneous  fusion  (§  236),  at  a  red  heat,  and  becomes 
decomposed  at  a  still  higher  degree  of  temperature  (its 
acid  being  reduced  to  its  elements,  oxygen  and  nitrogen). 
It  crystalizes  in  6  sided  prisms.  When  mixed  with 
common  salt  (Chloride  of  soda)  it  becomes  partly  de- 
composed, and  nitrate  of  soda  and  chloride  of  potassium 
are  formed.  Thrown  upon  red  coals,  it  promotes  their 
combustion  by  giving  off  oxygen.  A  mixture  of  sulphur 


NITRATE    OF    POTASH.  261 

and  nitre  thrown  into  a  red  hot  crucible  will  immediately 
burn  with  a  vivid  .light.  A  mixture  of  phosphorus  and 
nitre  may  be  inflamed  by  the  stroke  of  a  hammer,  with 
great  detonation. 

Uses  of  Saltpetre.  Nitre,  or  saltpetre  is  used  princi- 
pally, 

1.  In   the  preparation  of  fulminating  powder. 

2.  In  the  manufactory  of  gunpowder. 

3.  In  the  manufactory  of  sulphuric  acid. 

4.  In  the  manufactory  of  glass. 

5.  In  medicine. 

6.  In  domestic  economy  (for  corning  beef  and  preserv- 
ing grain). 

Three  parts  of  nitre,  two  of  potash,  and  one  of  sulphur,  when 
mixed  together  and  heated,  explode  with  a  loud  noise,  on  ac- 
count of  the  great  quantity  of  nitrogen  which  is  suddenly  giv- 
en off.  Hence  the  name  fulminating  powder. 

§  240.  Gunpowder.  The  most  remarkable  applica- 
tion of  nitre  is  in  the  manufactory  of  gunpowder.  This 
is  a  mixture  of  nitre,  charcoal,  and  sulphur.  The  propor- 
tions of  these  ingredients  vary  according  to  the  purpose  for 
which  the  powder  is  to  be  used.  It  consists  generally  of 
five  parts  of  nitre,  one  part  of  sulphur,  and  one  of  charcoal. 
These  are  moistened  and  finely  powdered,  either  by  wood- 
en pestles,  or,  in  modern  times,  by  marble  rollers,  and  the 
paste  thus  obtained  is  then  granulated  and  dried. 

Table  exhibiting  different  sorts  of  Powder. 

INGREDIENTS. 

nitre,     sulphur,  charcoal. 

Prussian  military  powder,       .     .     .     75  .      11.5  13.5 

French  and  English, .75        12.5  12.5 

English  Dartfort, .     .     79.7        7.82  12.48 

Swedish, 76          9  16 

Austrian  musket  powder,    ....     72         16  17 

Properties  of  good  powder.  It  must  have  a  bluish  slate-color 
(a  dark  or  black  color  shows  too  great  a  proportion  of  charcoal, 
or  dampness).  The  grains  must  be  round  and  even,  and  not 
too  readily  crumble  between  the  fingers.  When  ignited,  the 
whole  must  be  quickly  inflamed,  without  a  crackling  noise,  and 


262  NITRATE    OF    SODA. 

without  singing- the  surface  on  which  it  is  placed.  A  yel- 
low or  black  residue  after  combustion  is  a  proof  of  too  great  a 
proportion  of  sulphur  or  charcoal,  and  a  crackling  noise  during 
combustion  shows  that  the  powder  is  either  damp  or  that  there 
are  other  salts  mixed  with  the  nitre.  In  order  that  gunpow- 
der shall  retain  its  qualities,  it  must  be  protected  from  damp- 
ness. For  this  purpose  it  is  best  kept  in  leather  bags. 

Gunpowder  ignites  at  a  temperature  of  419°  Fahrenheit, 
and  its  subsequent  expansion  and  propelling  power  is  owing 
to  a  prodigious  quantity  of  nitrogen,  carbureted  hydrogen, 
and  sulphurous  acid  gas  in  connection  with  a  large  propor- 
tion of  steam,  which  are  given  off  instantaneously  during 
its  combustion.  The  use  and  effect  of  powder  are  suffi- 
ciently known. 

The  powder  contained  in  the  cartridges  of  common  fire-arms 
is  never  wholly  ignited  ;  part  of  it  is  always  expelled  without 
adding  to  the  effect  of  the  piece.  By  the  use  of  percussion-caps 
(see  Fulminates)  a  more  powerful  stream  of  fire  is  created,  in 
consequence  of  which  the  powder  ignites  more  thoroughly, 
and  it  has  been  found  upon  experiment  that  a  percussion-gun 
produces  the  same  effect  with  only  four  fifths  of  the  quantity 
of  powder  which  is  needed  for  the  charge  of  a  musket  with  a 
common  lock. 

2.     Nitrate  of  Soda. 

Chemical  Composition  :     1  equiv.  of  nitric  acid  =  54 
1  equiv.  of  soda  (oxide  of  sodium)  =  32 

Consequently,  chemical  equiv.  of  nitrate  of  soda  =  86 

§  241.  Nitrate  of  soda,  also  under  the  name  of  cubic 
nitre,  is  found  among  native  nitre  in  Spain,  India,  and 
America,  particularly  in  Peru,  where  layers  of  more  than 
two  miles  in  length  have  lately  been  discovered.  It  may 
also  be  produced  artificially  by  saturating  nitric  acid  with 
soda.  Its  taste  is  cooling,  pungent,  and  bitter,  though 
less  so  than  that  of  nitrate  of  potash.  It  burns  with  an 
orange-colored  light,  three  times  slower  than  powder, 
wherefore  it  is  used  in  fire-works.  (Pyro-technia). 


NITRATE    OF    AM  M  ON  I  A. -OF    LIME.  263 


3.     Nitrate  of  Ammonia. 

Chemical  Composition  :     1    equiv.    of  nitric  acid  =  54 

1     do.          of  ammonia  =  17 

to  which  is  added  1     do.  of  water  =    9 


Consequently,  chem.  equiv.  of  nitrate  of  ammonia  =  80. 

§  242.  This  is  a  salt  produced  by  dropping  a  so- 
lution of  ammonia  into  dilute  sulphuric  acid.  It  crys- 
talizes  in  needles  (four  or  six  sided  prisms)  which  have 
a  lustre  like  silk.  They  are  colorless,  have  a  bitter,  cool- 
ing, pungent  taste,  attract  easily  moisture  from  the  atmos- 
phere, explode  when  thrown  on  burning  coals,  and  produce 
great  cold  when  dissolved  in  water.  There  is  but  little 
or  no  use  made  of  this  salt  in  the  arts. 

4.     Nitrate  of  Lime. 

Chemical  Composition  :     1  equiv.    of  nitric  acid  =  54 
1       do.  of  lime  =  28  * 


Consequently,  chemical  equiv.  of  nitrate  of  lead  =  82. 

§  243.  Nitrate  of  lime  occurs  in  small  quantities  in 
well  and  pump  water,  and  among  the  nitre  which  collects 
on  walls  or  on  the  surface  of  the  earth.  It  is  also  produced 
by  dissolving  a  salt  called  carbonate  of  lime  in  nitric  acid 
(the  lime  combining  with  the  nitric  acid  and  the  carbonic 
acid  being  set  free).  It  crystalizes  in  colorless,  six-sided 
prisms,  attracts  moisture  from  the  air,  and  deliquesces  (see 
§  235).  It  is  dissolved  by  one  fourth  its  weight  of  cold 
water,  (in  warm  water  it  melts  sooner)  and  by  equal  parts 
of  hot  alcohol.  Its  taste  is  bitter,  sharp  and  cooling. 
When  heated,  it  gives  off  oxygen  gas,  and  the  residue 
emitting  in  the  dark  a  white,  beautiful  light,  is  known  by 
the  name  of  Baldwin's  Phosphorus.  It  detonates  weakly 
when  thrown  on  burning  coals,  and  is  chiefly  used  in  the 
preparation  of  saltpetre. 


264  NITRATES  OF  MERCURY, 

5.     Proto-nitrate  and  Per-nitrate  of  Mercury. 

Chemical  Composition.      Proto-nitrate  of  mercury    is 
composed  of  1  equivalent  of  nitric  acid  =    54 
1.  equivalent  of  protoxide  of  mercury  =  208 

Consequently,  chem.  equivalent  of  proto-nitrate 

of  mercury  =  262. 

Per-nitrate  of  Mercury 

is  composed  of  1  equivalent  of  nitric  acid  =    54 
2  equiv.  of  per-oxide  of  mercury  (each  =  21 6)  =  432 

Consequently,  chemical  equivalent  of  per-nitrate 

of  mercury  =  486. 

§  244.  The  proto-nitrate  of  mercury  is  a  salt,  which, 
as  we  may  suppose  from  its  name,  is  composed  of  protoxide 
of  mercury  and  nitric  acid.  It  is  obtained  by  pouring 
quicksilver  upon  weak  dilute  nitric  acid,  kept  at  a  low 
temperature.  Oxide  of  nitrogen  is  slowly  given  off,  and 
a'  colorless  solution  formed,  which  deposites  colorless, 
transparent  crystals,  of  a  sharp,  pungent  taste.  When 
exposed  to  daylight  they  become  yellow,  and  stain  the  skin 
with  a  purple  color. 

The  per-nitrate  of  mercury  is  a  combination  of  the  per- 
oxide of  mercury  with  nitric  acid.  It  is  obtained  in  the 
same  manner  as  the  proto-nitrate,  only  that  the  solution 
must  be  heated  and  boil  for  some  time.  When  the  liquid 
evaporates,  long,  prismatic  crystals  are  formed,  which 
have  a  pungent,  sharp  taste,  attract  moisture,  and  be- 
come yellow  by  exposition  to  day-light.  Both  nitrates  of 
quicksilver  are  used  in  medicine.  They  are  also  employ- 
ed in  the  art  of  gilding  by  means  of  gold  amalgams. 

6.     Nitrate  of  Silver. 

Chemical  Composition  :    1  equiv.  of  nitric   acid  =    54 
1   do.    of  oxide  of  silver  =  118 


Chemical  equivalent  of  nitrate  of  silver  =  172. 
245.     This  salt,  fused  and  cast  into  small  bars,  forms 


NITRATE     OF    SILVER — OF    LEAD.  265 

the  well  known  lunar  caustic,  extensively  used  in  surgery. 
It  is  obtained  from  a  solution  of  fine  silver  in  nitric  acid. 
Deutoxide  of  nitrogen  is  given  off,  and  the  nitrate  shoots 
into  colorless,  transparent  crystals,  which  have  a  sharp, 
hitler,  metallic  taste,  and  upon  being  exposed  to  light, 
turn  dark.  It  is  dissolved  in  equal  parts  of  cold  water, 
and  in  4  parts  of  boiling  alcohol.  A  number  of  bodies 
have  the  power  of  decomposing  it,  and  when  mercury  is 
poured  upon  it,  the  silver  is  precipitated  in  form  of  a  tree, 
which  affords  one  of  the  most  beautiful  and  striking  ex- 
periments that  can  be  made,  to  beginners.  It  destroys 
speedily  all  vegetable  and  animal  formations  (hence  its 
use  in  surgery ),  or  stains  them  first  with  a  white,  but  upon 
exposition  to  light,  with  a  permanent  black  color.  The 
latter  property  is  taken  advantage  of  in  the  preparation  of 
indelible  or  marking  ink. 

The  linen  or  cotton  which  is  to  be  marked  is  first  moist- 
ened with  a  solution  of  carbonate  of  soda,  upon  which,  when 
perfectly  dry,  the  letters  are  written  with  a  solution  of  ni- 
trate of  silver,  mixed  with  gum  arabic,  and  a  little  India 
ink.  Upon  exposition  to  light,  the  letters  turn  permanently 
black. 

7.     Nitrate  of  Lead. 

Chemical  Composition  :     1  equiv.  of  nitric  acid  =    54 
1  equiv.  of  protoxide  of  lead  s=  112 


Consequently,  chemical  equiv.  of  nitrate  of  lead  =  166. 

§  246.  This  salt  is  quickly  obtained  from  a  solution 
of  oxide  of  lead  in  nitric  acid.  It  crystalizes  in  colorless, 
transparent  (sometimes  white,  opaque)  octahedrons,  which 
have  a  pungent,  cooling,  sweetish  taste.  It  is  dissolved 
in  seven  times  its  weight  of  cold  water  (much  less  boiling 
water  is  required),  melts  when  heated,  gives  off  oxygen 
and  leaves  oxide  of  lead.  It  is  used  in  cotton-printing. 
With  Chromate  of  potassium  it  produces  a  beautiful  or- 
ange color. 

23 


266  NITRATE    OF    COPPER-CHLORATES. 


8.     Nitrate  of  Copper. 

Chemical  Composition  :    1  equiv.  of  nitric  acid  =    54 
1  equiv.  of  per-oxide  of  copper  =    80 


Consequently,  chem.  equiv.  of  nitrate  of  copper  =  134. 

§  247.  Nitrate  of  copper  is  obtained  by  dissolving 
copper  in  dilute  nitric  acid.  The  salt  crystalizes  in  prisms 
of  a  beautiful  sapphire-blue  color,  has  a  sharp,  caustic 
taste ;  deliquesces  (§  235)  easily,  and  dissolves  readily  in 
water.  It  is  used  in  the  preparation  of  blue  colors  in 
cotton  printing,  and  as  a  means  of  oxydizing  metals. 

B.     CHLORATES. 

<§>  248.  Properties  of  the  chlorates.  These  salts  are 
in  their  properties  similar  to  the  nitrates.  They  are  all 
products  of  art,  and  are  easily  decomposed  by  heat.  They 
give  off  part  of  their  oxygen  and  are  totally  consumed 
when  thrown  upon  burning  coals.  We  shall  only  describe 
a  few  of  them. 

Chlorate  of  Potash. 

Chemical  Composition  :     1  equiv.  of  chloric  acid  =    76 
I      do.  of  potash  =    48 


Consequently,  chem.  equiv.  of  chlorate  of  potash  =  124. 

§  249.  This  salt  is  produced  by  conducting  as  much 
chlorine  into  a  solution  of  pure  potash  as  the  latter  is  ca- 
pable of  taking  up.  The  solution  is  then  suffered  to  cool 
and  evaporate,  when  the  salts  will  shoot  in  crystals  similar 
in  appearance  to  mother  of  pearl. 

The  solution  of  potash  is  placed  in  a  three-necked  bottle  A, 


CHLORATE    OF    POTASH.  267 

shaped   as  represented  in   the  adjoining  figure.     This  bottle 
iff.  CXXXV. 


G  R 

communicates  by  means  of  a  pipe,  with  the  globe  G,  and  the 
retort  R,  into  which  some  black  oxide  of  manganese  is  intro- 
duced in  a  state  of  fine  powder.  The  apparatus  being  thus 
arranged,  muriatic  acid  is  poured  upon  the  oxide  of  manga- 
nese through  the  safety  tube  T,  which  to  prevent  the  immedi- 
ate escape  of  the  chlorine  gas  must  be  shaped  as  represented 
in  the  figure,  and  a  gentle  heat  applied  to  the  retort.  Chlorine 
will  be  given  off  and  pass  over  into  the  solution  of  potash,  un- 
til the  solution  is  saturated,  after  which  the  excess  of  gas  will 
escape  through  the  safety  tube.  When  the  saturated  solu- 
tion is  afterwards  evaporated  at  a  low  heat,  small  shining  crys- 
tals are  obtained,  which  are  the  pure  chlorate  of  potash. 

§  250.  Properties.  Its  taste  is  cooling  but  nauseous. 
It  is  besides,  inodorous,  sparingly  soluble  in  cold  water, 
becomes  liquid  by  a  gentle  heat,  but  gives  off  its  oxygen 
and  becomes  decomposed  by  high  temperatures.  When 
mixed  with  combustible  substances  a  smart  stroke  or  per- 
cussion may  inflame  it,  and  a  violent  detonation  takes 
place.  (Half  a  tea-spoon  full  wrapt  in  a  piece  of  paper 
and  briskly  struck  with  a  hammer,  gives  a  report  like  a 
gun).  It  is  used  in  the  comstruction  of  instantaneous  light 
matches. 

Instantaneous  light  matches.  The  ends  of  the  matches  are 
covered  with  a  red  mass,  consisting  of  30  parts  of  chlorate  of 
potash,  10  of  sulphur,  and  a  little  gum  water.  When  these 
matches  are  dipped  in  a  little  bottle,  filled  with  concentrated 
sulphuric  acid,  enough  heat  is  produced  for  the  sulphur  to  ig- 
nite, that  is,  to  combine  with  the  oxygen  which  is  given  off. 

REMARK.  Bertholet,  a  French  chemist,  endeavored  to  use 
chlorate  of  potash  instead  of  nitre  in  the  manufactory  of  gun- 


268  CHLORATE    OP    SODA OF    AMMONIA. 

powder.  The  powder  thus  obtained  is  very  powerful,  but  so 
highly  inflammable  that  many  people  lost  their  lives  during  its 
preparation,  or  in  the  attempt  of  packing  or  transporting  it. 
It  is  nevertheless  used  in  fire-works,  for  the  red  light  in  thea- 
tres, and  in  the  construction  of  Congreve's  rockets. 

2.      Chlorate  vj  Soda. 

Cliemical  Composition  :     1  equiv.  of  chloric  acid  =    76 
1      do.  of  soda  =    32 

Consequently,  chemical  equiv.  of  chlorate  of  sod  a  =  108. 

§  251.  Clilorate  of  soda  is  obtained  in  the  same  man- 
ner as  chlorate  of  potash  (taking  soda  instead  of  potash). 
It  crystalizes  in  cubes,  tastes  almost  like  chlorate  of  pot- 
ash, is  soluble  in  three  parts  of  cold  (much  less  of  warm) 
water,  but  is  more  easily  dissolved  in  spirits  of  wine.  Its 
other  properties  resemble  those  of  nitrate  of  potash. 

3.     Hydro-chlorate  (Muriate)  of  Ammonia. 

Chemical  Composition  :     1  equiv.  of  muriatic  acid  =  37 

1     do.          of  ammonia  =  17 

To  this  must  yet  be  added,  1  equiv.  of  water  =    9 


Consequently,  chemical  equiv.  of  hydro-chlorate 

of  ammonia  =  63. 

5)  252.  This  salt,  commonly  called  sal-ammoniac,  is 
found  in  all  volcanic  countries,  in  hair-like  crystals,  or 
spherical ;  also  in  form  of  a  powder,  colored  by  an  admix- 
ture of  sulphur  or  oxide  of  iron.  It  is  manufactured  on  a 
large  scale  from  the  refuse  of  animal  substances,  (such  as 
hoofs,  horns,  claws,  &c),  and  may  also  be  obtained  by 
neutralizing  a  solution  of  ammonia  with  muriatic  acid. 
When  the  liquid  is  evaporated,  the  salt  shoots  in  color- 
less crystals,  of  a  sharp,  pungent,  saline  taste.  It  is  easi- 
ly volatilized,  emits  white  vapors,  and  is  very  soluble  in 
water.  It  is  used  for  a  variety  of  purposes  in  the  arts, 
particularly  in  tinning  copper  ware,  to  prevent  the  oxida- 
tion of  that  metal. 


CHLORIDE    OF     LIME.  269 


.  C.     CHLORIDES. 

§  253.  Pure  chlorine  combines  with  potash,  soda  and 
other  oxides  of  metals.  All  these  combinations  have  pow- 
erful bleaching  powers  and  smell  after  chlorine.  The 
most  remarkable  and  useful  of  them  is 

Chloride  of  Lime. 

Chemical  Composition  :     1  equivalent  of  chlorine  =  36 
2  equivalents  of  lirne  (each  =  28)  =  56 


Consequently,  chemical  equiv.  of  chloride  of  lime  =  92. 

^  254.  This  compound  is  manufactured  upon  a  very 
extensive  scale.  For  this  purpose  chlorine  is  passed  into 
rooms  in  which  fine-powdered,  fresh-slacked  lime  is  sub- 
mitted to  its  action.  The  gas  combines  quickly  with  the 
lime  ;  but  as  this  combination  is  accompanied  by  an  evo- 
lution of  heat,  through  which  chlorate  of  lime  would  be 
formed,  it  is  necessary  to  let  the  gas  slowly  into  the  room, 
commonly  two  days  in  succession)  or  to  surround  the  room 
with  cold  water.  It  is  calculated  that  1  cwt.  of  lime  yields 
commonly  1J  cwt.  of  chloride  of  lime. 

^  255.  Properties.  Dry  chloride  of  lime  is  a  white 
powder  with  a  faint  smell  of  chloric  acid  (not  chlorine) 
and  a  strong,  pungent  taste.  By  long  keeping,  especial- 
ly when  moist,  it  absorbs  carbonic  acid  gas  from  the  at- 
mosphere, whereby  it  becomes  converted  into  carbonate  of 
lime. 

Applications  of  Chloride  of  Lime.  It  is  extensively 
used  in  the  process  of  bleaching,  on  which  account  it 
is  commonly  called  bleaching  powder,  and  possesses 
the  remarkable  property  of  cleansing  the  atmosphere 
from  the  infective  effluvia  and  exhalation  of  putrefying 
substances,  and  communicating  to  it  a  pleasant  freshness. 
For  this  purpose  fumigation  and  sprinkling  with  chloride 
of  lime  cannot  be  too  strongly  recommended,  in  case  of 
contagious  diseases  in  hospitals,  prisons,  alms-houses,  and 
all  places  of  public  assembly. 
23* 


270  CHLORIDE    OF     SILVER. 


D.     MURIATES,  (OR  CHLORIDES). 

§256.  Properties  of  the  Muriates,  or  Chlorides.  The 
salts  belonging  to  this  class  are  all  distinguishable  by  the 
following  characterizing  properties  : 

1.  They  remain  all  unaltered  by  the  admixture  of  com- 
bustible  substances   (such  as   hydrogen,  sulphur,  carbon, 
&c),  to  whatever  degree  of  heat  they  may  be   exposed. 
Common  salt,  for  instance,  which  is  a  chloride  of  sodium, 
may  be  mixed  with  charcoal  and  heated,  without  changing 
in  the  least,  its  properties. 

2.  They  are  all  decomposed  by  sulphuric  acid,  giving 
off  muriatic  acid,  &c. 

3.  They  are  all  soluble  in  water. 

REMARK.  It  is  to  be  remarked  that  in  regard  to  the  com- 
binations of  muriatic  acid  with  the  different  salifiable  oxides 
of  metals,  there  are  two  different  opinions  entertained  by  mod- 
ern chemists.  Some  of  them  believe  that  when  muriatic  acid 
is  poured  upon  an  oxide  of  a  metal,  a  mutual  decomposition 
takes  place  ;  the  chlorine  of  the  acid  combines  with  the  metal 
and  forms  a  chloride,  while  the  hydrogen  of  the  muriatic  acid 
combines  with  the  oxygen  of  the  oxide  to  water,  in  which  the 
chlorine  is  afterwards  dissolved.  Hence  the  appellation  of 
chlorides.  Others,  however,  take  the  solution  of  a  metallic 
oxide  in  muriatic  acid,  for  a  hydrate  :  believing  the  water 
chemically  combined  with  the  solution.  For  this  reason  they 
call  the  salts  thence  obtained,  muriates.  It  is,  of  course,  in- 
different for  practical  purposes,  to  which  of  these  two  opinions 
we  adhere,  and  we  shall  therefore  distinguish  these  salts  in 
future  by  the  name  of  chlorides. 

1 .     Chloride  of  Silver. 

Chemical  Composition :    I  equivalent  of  chlorine  =    36 
1     do.    of  oxide  of  silver  =  110 


Consequently,  chem.  equiv.  of  chloride  of  silver  =  146. 

This  salt  has  already  been  described  in  Chapter  III,  §  184, 
page  201,  among  the  binary  combinations  of  silver. 


CHLORIDE  OF  GOLD.  — OF  PLATINUM.    271 

2.     Chloride  of  Gold. 
Chemical  Composition  not  precisely  understood. 

§  257.  Chloride  of  gold  is  prepared  from  a  solution  of 
gold  in  nitro-muriatic  acid.  The  solution  has  commonly 
a  strong  sour  taste,  ]ias  a  beautiful  yellow  color,  and  leaves 
upon  evaporation  a  reddish-yellow,  saline  mass,  which  still 
contains  some  muriatic  acid,  and  is  soluble  in  water.  If 
this  salt  be  gently  heated,  chlorine  is  given  off,  and  its 
yellow  color  is  changed  into  red.  Both  the  yellow  and 
the  red  salt  deliquesce,  have  a  sour,  astringent,  nauseous 
taste,  and  are  highly  poisonous.  They  are  easily  soluble 
in  water,  ether  and  alcohol.  These  solutions  become  de- 
composed by  exposition  to  daylight,  (still  better  by  solar 
light)  whereby  gold  is  precipitated.  The  salts  themselves 
are  likewise  decomposed  by  light  and  heat,  (chloride  of 
gold,  and  finally  simple  gold  remains).  The  pure  chloride 
of  gold  is  used  in  several  preparations  of  gold  ;  in  the  man- 
ufactury  of  gold-purple,  a  precious,  beautiful  color,  em- 
ployed in  glass  and  porcelain  painting,  and  particularly  in 
the  gilding  of  steel,  for  which  purpose  it  is  extensively 
employed. 

3.     Chloride  of  Platinum. 

Chemical  Composition :    2  equivalents  of  chlorine 

(each  =  36)  =    72 
1  equivalent  of  platinum  =    96 

Consequently,  chern.  equiv.  of  chloride  of  platinum  =  168. 

§  258.  A  DOUBLE  Chloride  (bichloride)  of  platinum 
may  be  obtained  by  the  solution  of  platinum  in  nitro-muri- 
atic acid.  When  the  solution  is  carefully  evaporated  a 
blackish  brown  mass  is  obtained  (as  long  as  it  contains 
water  it  appears  red)  which  has  a  nauseous,  metallic,  sharp 
taste,  acts  as  a  poison  on  the  animal  body,  and  is  easily 
soluble  in  water,  ether  and  alcohol.  It  communicates  to  or- 
ganic substances  a  purple  color,  and  when  heated  gives  off 
part  of  its  chlorine,  by  which  means  a  simple  chloride  of 


272  CHLORIDE    OF    COPPER.  — OF    TIN. 

platinum  remains.     This  is  a  greyish  powder,  which  is  sol- 
uble only  in  concentrated  muriatic  acid. 

4.     Chloride  of  Copper. 

Chemical   Composition :      2  equiv.  of   chlorine 

(each  =  36)  =    72 
1  equiv.  of  copper  =    64 


Consequently,  chem.  equiv.  of  chloride  of  copper  =  136. 

§  259.  Double  chloride  of  copper  is  obtained  as  a 
hydrate  by  a  solution  of  oxide  of  copper  in  muriatic  acid. 
In  an  an-hydrous  state  it  may  be  obtained  by  being  gently 
heated.  If  the  temperature  be  still  further  increased,  part  of 
the  chlorine  is  given  off  and  the  simple  chloride  of  copper 
remains.  (An-hydrous  chloride  of  copper  may  also  be  ob- 
tained at  once  by  heating  thin  plates  of  copper,  and  im- 
mersing them  in  chlorine.  The  copper  does  then  burn 
with  a  green  light,  and  the  product  of  the  combustion  is 
the  an-hydrous  chloride).  The  an-hydrous  combination 
has  a  yellowish  brown  color,  but  absorbs  moisture  so  rap- 
idly from  the  air  that  its  color  becomes  soon  changed  into 
green.  Mixed  with  35  per  cent  of  water  it  crystalizes  in 
beautiful  green  needles,  which  have  a  sharp  metallic  taste, 
deliquesce,  and  are  easily  dissolved  by  spirits  of  wine. 
Such  a  solution  burns  with  a  beautiful  green  flame,  and 
is  used  in  fire-works  and  for  theatrical  purposes. 

5.  Chloride  of  Lead. 

This  salt  has  already  been  spoken  of,  among  the  binary 
combinations  of  lead,  on  page  214. 

6.  Chloride  of  Tin. 

^  260.  Chloride  of  Tin,  (  Tin  salt)  is  obtained  in  an 
an-hydrous  state ;  when  tin-filings  are  heated  with  mu- 
riatic acid  gas ;  the  hydrogen  of  the  muriatic  acid  gas 
is  given  off,  and  the  chlorine  combines  with  the  tin.  Jt  is 
a  grey,  half-transparent  substance,  of  a  glassy  fracture, 
which  melts  and  becomes  volatilized  at  a  red  heat.  Chlo- 


CHLORIDE    OF    COBALT.  273 

ride  of  tin  combined  with  water  (muriate  of  tin),  is  ob- 
tained from  a  solution  of  tin-filings  in  muriatic  acid.  The 
solution  has  a  brown  color,  which  upon  cooling  and  con- 
centrating, forms  colorless,  transparent  crystals  of  a  disa- 
greeable taste  and  smell,  and  highly  poisonous.  They 
deliquesce,  and  are  easily  soluble  in  water.  Chloride  of 
tin  is  used  in  cotton  and  silk  dyeing. 

Per-chloridt  of  tin  is  obtained  by  a  distillation  of  one  part  of 
tin-filings  with  four  parts  of  corrosive  sublimate.  Ttis  a  color- 
less, transparent  liquid,  of  a  very  disagreeable  smell,  which,  in 
contact  with  atmospheric  air,  emits  dense  white  vapors.  It 
absorbs  water  rapidly.  By  adding  to  it  one  third  of  its  weight 
of  water  it  becomes  converted  into  a  thick,  white  substance, 
known  by  the  name  of  tin-butter. 

7.     Chloride  of  Cobalt. 

§  261.  This  chloride  is  produced  by  boiling  a  solution 
of  cobalt  in  concentrated  muriatic  acid.  The  solution  has 
a  beautiful  red  color  (when  concentrated  and  warm  it  is 
blue),  and  crystalizes  with  water  in  dark  red  prisms,  which 
have  an  astringent  taste,  and  are  soluble  in  water  and  al- 
cohol. 

A  dilute,  weak  solution  of  chloride  of  cobalt,  which  is  almost 
colorless,  is  used  for  a  sort  of  sympathetic  ink.  The  charac- 
ters written  with  it,  when  dry  are  invisible ;  but  when  the 
paper  is  held  before  a  fire  they  become  blue.  Upon  cooling, 
the  color  disappears  again ;  but  may  again  be  produced  by 
exposition  to  heat.  When  the  experiment  is  often  repeated, 
the  characters  become  finally  fixed  with  a  dark  red  color. 

Chlorine  combines  yet  with  iron,  nickel,  cerium,  and 
most  of  the  other  metals. 

E.     SULPHATES. 

§  262.  Properties  of  the  Sulphates.  These  salts  are 
formed  (as  the  name  indicates)  by  the  combination  of  sul- 
phuric acid  with  the  different  salifiable  bases.  Many  of 
them  are  products  of  nature,  and  are  of  great  usefulness 
to  the  arts.  They  may  be  marked,  as  a  class,  by  the  fol- 
lowing properties  : 


274  SULPHATE    OF     POTASH.— OF    SODA. 

1.  When  an  acid  is  poured  upon  them,  at  common  tem- 
peratures, they  neither  effervesce  nor  give  off  any  vapors. 

2.  They  are  all  decomposed  by  high  temperatures,  with 
the  exception,  however,  of  the  sulphates  of  potash,  soda, 
lithia,  baryta,  strontia,  lime,  magnesia,  and  lead. 

3.  They  are  all  decomposed  by  carbon  under  the  influ- 
ence of  an  intense  heat. 

1.     Sulphate  of  Potash. 

Chemical  Composition  :    I  equiv.  of  sulphuric  acid  =  40 
1     do.  of  potash  =  48 

Consequently,  chem.  equiv.  of  sulphate  of  potash  =  88. 

§  263.  This  salt  occurs  in  common  stone  or  table  salt, 
in  alumine.  and  in  many  vegetables.  It  is  obtained,  as 
a  secondary  product  in  salines,  and  in  the  preparation  of 
nitric  and  sulphuric  acid.  It  crystalizes  in  prisms,  has  a 
sharp,  bitter,  saline  taste,  remains  fixed  in  fire,  and  is  sol- 
uble in  12  parts  of  cold  water.  It  is  used  in  medicine, 
and  in  the  preparation  of  alum,  glass,  and  saltpetre. 

2.     Sulphate  of  Soda. 

Chemical  Composition :    \  equiv.  of  sulphuric  acid  =  40 
1     do.  of  soda  =  32 


Consequently,  chem.  equiv.  of  sulphate  of  soda  =  72. 

§  264.  This  sulphate  (known  in  medicine  by  the 
name  of  Glauber's  salts)  occurs  in  all  three  kingdoms  of 
nature.  It  is  sometimes  (for  instance,  in  Spain)  found  on 
the  surface  of  the  earth,  and  adheres  to  damp  walls.  It  is 
also  found  in  mineral  waters,  and  in  lakes.  It  is  obtained 
in  large  quantities  by  the  decomposition  of  common  salt 
by  means  of  sulphuric  acid  (whereby  muriatic  acid  is  given 
off).  It  crystalizes  in  colorless,  transparent  prisms,  which 
have  a  bitter,  cooling  taste,  and  when  exposed  to  the  at- 
mosphere, changes  into  a  white  powder,  and  deliquesce  at 
a  gentle  heat.  This  salt  is  not  soluble  in  alcohol.  It  is 
used  in  the  artificial  preparation  of  carbonate  of  soda  and 
in  the  manufactury  of  glass;  but  particularly  in  medicine. 


SULPHATE  OF  LIME.— OF    MAGNESIA.  275 

3.     Sulphate  of  Lime. 

Chemical  Composition :    1  equiv.  of  sulphuric  acid  =  40 

1     do.  of  lime  =28 

to  which  are  added  2  equiv.  of  water  (each  =  9)  =  18 


Consequently,  chem.  equiv.  of  sulphate  of  lime  =  86. 

§  265.  Sulphate  of  lime  occurs  abundantly  in  the  min- 
eral kingdom,  as  gypsum,  selenite,  alabaster,  and  plaster- 
stone  ;  more  rarely  in  vegetable  and  animal  substances. 
Selenite  crystalizes  in  right  or  oblique  prisms,  which  are 
transparent,  and  either  colorless,  or  grey,  yellow,  or  brown, 
and  have  a  lustre  between  glass  and  mother  of  pearl. 

Mabaster  has  more  of  a  lamellar  texture,  and  a  white,  yel- 
lowish-grey, or  reddish  color.  The  most  compact  kind  of 
gypsum, 

Plaster-stone,  contains  often  remains  of  animal  and  vegeta- 
ble substances.  It  is  very  liable  to  destruction,  and  crumbles 
easily  into  dust. 

Gypsum  may  be  produced  by  the  action  of  sulphuric  acid  on 
lime,  in  which  case  it  is  obtained  in  white,  silky  crystals,  which 
are  not  easily  soluble  in  water.  By  burning,  it  becomes  re- 
duced to  a  white  powder,  called  Plaster  of  Paris.  The  uses 
of  this  salt  are  manifold.  It  serves  to  polish  precious  stones 
and  pearls,  and  is  used  for  various  ornaments  (tables,  clocks, 
&c),  for  taking  casts  and  moulds,  for  cements  and  stuccos  in 
architecture,  in  the  manufactory  of  porcelain,  and  in  domestic 
economy  as  a  manure  for  meadows  and  clover  fields.  Mixed 
with  animal  glue,  and  polished  with  sand-stone,  it  resembles 
marble. 

4.     Sulphate  of  Magnesia. 

Chemical  Composition  :    1  equiv.  of  sulphuric  acid  =  40 
1     do.  of  magnesia  =20 


Consequently,  chemical   equivalent   of  sulphate 

of  magnesia  =  60. 

§  266.  Sulphate  of  magnesia  (bitter  salt,  Epsomsalt) 
is  contained  in  sea  and  mineral  waters,  which  on  that 
account  have  a  bitter  taste  (Epsom,  in  England,  whence 
the  name  of  the  salt).  It  is  also  found  in  small  quanti- 


276          SULPHATES  OF  MERCURY. 

ties  on  the  surface  of  the  earth  and  in  the  ashes  of  burnt 
vegetables.  It  may  likewise  be  obtained  by  the  action  of 
strong  sulphuric  acid  on  magnesia,  by  which  much  heat 
is  evolved  (sometimes  enough  to  cause  ignition).  It  crys- 
talizes  in  colorless,  four-sided  prisms,  which  are  capable 
of  aqueous  and  igneous  fusion,  but  forms,  when  exposed  to 
very  high  temperatures,  a  kind  of  enamel.  This  salt  is 
extensively  used  in  medicine. 

5.     Sulphates  of  Mercury. 

Sulphuric  acid  combines  with  the  protoxide  and  per-ox- 
ide  of  mercury  (see  Chap.  Ill,  §  175,  and  §  176)  to  proto- 
sulphale  and  per-sulphate  of  mercury,  respectively. 

The  Proto-sulphate  of  Mercury 

is  composed  of  1  equivalent  of  sulphuric  acid  =    40 
1  equivalent  of  protoxide  of  mercury  =208 

Consequently,  chemical  equiv.  of  proto-sulphate 

of  mercury  =  248. 

Per-sulphate  of  Mercury 

is  composed  of  1    equivalent  of  sulphuric    acid  =    40 
1          do.  ofper-oxideofmercury  =  216 

Consequently,   chemical   equivalent  of  per-sul- 
phate of  mercury  =  256. 

§  267.  Per-sulphate  of  mercury  (from  per-oxide  of 
mercury,  is  obtained  by  boiling  4  parts  of  quicksilver 
with  5  parts  of  concentrated  sulphuric  acid.  Sulphur- 
ous acid  gas  is  given  off,  and  the  liquid  upon  cooling 
deposites  a  saline  mass,  in  form  of  prismatic  crystals.  This 
salt  has  a  sharp,  metallic  taste,  and  is  by  the  agency  of 
water,  immediately  separated  into  two  distinct  salts;  in  a 
sour  salt,  which  remains  in  a  stale  of  solution,  and  in  a 
basic,  which  is  precipitated.  The  basic  salt  has  a  yellow 
color,  but  becomes  black  when  exposed  to  solar  light  in  a 
state  of  moisture,  on  which  account  it  cannot  be  used  as  a 
dyeing  stuff. 


SULPHATE    OF    SILVER. -OF    COPPER.          277 

The  proto-sulphate  of  mercury  is  obtained  by  gently  heat- 
ing1 one  part  of  mercury,  with  one  and  a  half  parts  of  sulphuric 
acid.  It  is  but  sparingly  soluble  even  in  warm  water. 

6.     Sulphate  of  Silver. 

Chemical  Composition :    I  equiv.  of  sulphuric  acid  =    40 
1     do.   of  oxide  of  silver  =  118 


Consequently,  chem.  equiv.  of  sulphate  of  silver  =  158. 

§  268.  This  salt  is  immediately  obtained  by  a  solution 
of  silver  in  concentrated  sulphuric  acid.  It  is  with  diffi- 
culty soluble  in  water,  crystalizes  in  small  white  needles, 
has  a  metallic,  disagreeable  taste,  and  melts  when  heated, 
by  which  means  oxygen  and  sulphurous  acid  gas  are  giv- 
en off,  and  pure  metallic  silver  remains.  Sulphate  of  silver 
is  formed  whenever  silver  is  separated  from  gold  and  copper 
by  means  of  sulphuric  acid.  The  gold  is  not  touched 
by  this  acid  and  is  therefore  obtained  in  form  of  a  powder. 
The  silver  is  recovered  from  the  sulphate  by  the  action  of 
copper,  which  combines  with  the  acid  and  sets  the  silver 

free. 

• 

7.     Per-sulphate  of  Copper. 

Chemical  Composition  :     2   equiv.    of  sulphuric 

acid  (each  =  40)  =  80 

1  equiv.  of  per-oxide  of  copper  =  80 

to  which  is  added  10  equiv.  of  water  (each  =  9)  =  90 


Consequently,  chem.  equiv.  of  per-sulphate    of 

copper  =  250. 

§  269.  Per-sulphate  of  copper  (blue  vitriol)  occurs, 
in  a  state  of  solution,  in  copper-mines.  It  may  be  obtain- 
ed also  from  a  solution  of  copper  in  sulphuric  acid.  It 
forms  crystals  of  a  beautiful  azure  color,  which  have  a 
disagreeable  metallic  taste,  cause  nausea  and  vomiting 
when  taken  into  the  stomach,  and  become  converted  into 
a  white  powder  by  exposure  to  heat.  Blue  vitriol  is  solu- 
ble in  water  (not  in  spirits  of  wine).  Various  mixtures 

24 


278    SULPHATES    OF   IRON-BARYTA—AMMONIA. 

of  vitriol  are  used  in  the  dyeing  of  wool,  in  the  bronzing 
of  iron  ware,  in  the  coloring  of  gold,  in  medicine,  &/c. 

8.     Sulphate  of  Iron. 

Chemical  Composition :    1  equiv.  of  sulphuric  acid  =  40 
1  equiv.  of  protoxide  of  iron  =  36 

Consequently,  chem.  equiv.  of  sulphate  of  iron  =  76. 

§  270.  Sulphate  of  iron  (green  vitriol)  is  a  product 
of  nature,  which  is  found  in  coal  and  other  mines.  It  may 
also  be  obtained  from  a  solution  of  iron  in  dilute  sulphu- 
ric acid.  It  crystalizes  in  green,  transparent  rhombs, 
which  have  a  sour,  astringent  taste  (like  ink),  and  become 
quickly  oxidized  in  contact  with  atmospheric  air.  At 
high  temperatures  it  falls  into  a  white  powder.  On  ac- 
count of  its  great  affinity  for  oxygen  it  is  used  foj  the  des- 
oxidation  of  indigo. 

9.  Sulphate  of  Baryta. 

Chemical  Composition  :    1  equiv.  of  sulphuric  acid  =   40 
I     do.    •         of  baryta  =    78 

Consequently,  chem.  equiv.  of  sulphate  of  baryta=  118. 

§  271.  Sulphate  of  baryta  (heavy  spar)  is  found 
crystalized  in  various  shapes  and  forms.  Its  color  is  a 
yellowish-white,  grey,  red,  or  blue,  with  a  strong  lustre 
(like  fat  or  glass).  When  heated  with  charcoal  it  fuses 
at  a  high  temperature  into  a  white,  opaque  enamel.  It  is 
used  as  a  permanent  white  pigment,  in  the  manufactory 
of  Wedgwood's  jasper  ware. 

10.  Sulphate  of  Ammonia. 

Chemical  Composition  :    1  equiv.  of  sulphuric  acid  =  40 

1     do.          of  ammonia  =  17 

to  which  is  added  1      do.  of  water  =   9 


Consequently,  chem.  equiv.  of  sulphate  of  ammonia  =  66. 
§  272.     This  salt  is  obtained  by  neutralizing  ammonia 


SULPHATE     OF     ALUMINE.  279 

with  sulphuric  acid.  It  has  a  sharp,  bitter  taste,  is  soluble 
in  water,  and  is  used  in  the  manufacture  of  sal-ammoniac, 
which  may  be  prepared  by  subliming  sulphate  of  ammonia 
with  common  salt.  It  crystalizes  in  small  prisms  by  tak- 
ing up  an  additional  equivalent  of  water,  by  which  means 
its  chemical  equivalent  is  increased  from  66  to  75. 

11.     Sulphate  of  Alumine. 

Chemical  Composition  :    1  equiv.  of  sulphuric  acid  =  40 
1     do.  ofalumine  =  17 


Consequently,  chem.  equiv.  of  sulphate  of  alurnine  =  57. 

§  273.  This  salt  is  a  product  of  nature,  and  occurs  in 
America,  in  Guadaloupe,  &c ;  but  is  also  obtained  by  art, 
when  pure  alumine  is  dissolved  in  sulphuric  acid.  The 
liquid,  when  evaporating,  forms  colorless,  semi-transparent, 
lamellar  crystals,  with  an  appearance  like  mother  of  pear]. 
It  has  a  sweet,  astringent  taste,  is  easily  soluble  in  water 
(not  in  alcohol),  and  gives  off  its  acid  when  exposed  to 
heat.  It  combines  with  the  sulphates  of  the  alkalies, 
arid  forms  thereby  a  class  of  salts  with  double  bases, 
well  known  by  the  name  of  alum.  Thus,  sulphate  of  alum- 
ine combines  with  sulphate  of  potash,  and  forms  a  salt 
which  has  two  bases,  alumine  and  potash.  Again,  sulphate 
of  alumine  combines  with  sulphate  of  soda,  the  product 
being  a  salt  with  the  two  bases,  alumine  and  soda,  and  so 
of  the  rest. 

§  274.  Alum.  The  two  kinds  of  salt  which  we  have 
just  chosen  for  an  example,  viz  :  sulphate  of  alumine  and 
potash,  and  sulphate  of  alumine  and  soda  are  by  far  the 
most  important  kinds  of  alum.  Both  are  products  of  nature  ; 
but  the  former  (sulphate  of  alumine  and  potash)  is  met 
with  in  much  greater  abundance,  particularly  in  the  neigh- 
borhood of  volcanos.  They  may  also  be  obtained  respect- 
ively by  pouring  sulphate  of  potash  or  soda  into  a  solution 
of  sulphate  of  alumine.  The  salts  thence  precipitated  crys- 
talize  in  octahedrons,  have  a  sweet,  astringent  taste,  and 
are  easily  soluble  in  water.  The  acid  of  the  first  salt  be- 
comes decomposed  by  heat,  whereby  it  becomes  light  and 


280  CARBONATE    OF    AMMONIA. 

spongy,  and  is  distinguished  by  the  name  of  burnt  alum. 
The  second  salt  is  by  heat  entirely  decomposed  into  its 
elements. 

Alum  is  an  important  article  of  commerce.  It  is  used  in 
dyeing  and  calico  printing,  in  tanneries  and  paper  manufac- 
tures ;  for  the  sizing  of  paper.  It  is  also  extensively  used  in 
medicine. 

The  sulphites  are  here  omitted,  because  they  are  of  less  im- 
portance to  the  arts,  and  their  properties  are  not  yet  sufficient- 
ly examined. 

F.     CARBONATES. 

§  275.  Characteristics  of  the  Carbonates.  The  salts 
of  this  class  may  be  known  by  the  following  properties  : 

1.  They  lose  their  acid  by   exposition  to  heat  (the  car- 
bonates of  potash,  soda  and  lithia  alone  excepted). 

2.  When  mixed  with  charcoal  they  are  all  decomposed 
by  a  high  heat. 

3.  They  are  all  decomposed  by  the  acids,  with  strnog 
effervescence  of  carbonic  acid. 

1.     Carbonate  of  Ammonia.    - 

Chemical  Composition  :     1  equiv.  of  carbonic  acid  =  22 
1     do.         of  ammonia  =  17 


Consequently,  chem.  equiv.  of  carbonate  of  ammonia=  39. 

§  276.  Two  volumes  of  dry  ammonia  combine  direct- 
ly with  one  volume  of  carbonic  acid  gas.  The  product  is 
carbonate  of  ammonia,  a  white,  crystaline  substance,  which 
has  a  strong  odor  of  ammonia,  and  is  readily  soluble  in 
water.  In  contact  with  the  atmosphere  part  of  the  vola- 
tile alkali  (ammonia)  escapes,  whereby  the  remainder  con- 
tains a  greater  portion  of  the  acid,  and  is  therefore  chang- 
ed into  bi  (double)  carbonate  of  ammonia. 

Smelling  Salts.  Sesqui-carbonate  (1^  carbonate)  of  ammo- 
nia, also  called  smelling  salts,  is  an  important  article  of  com- 
merce. It  is  obtained  on  a  large  scale  by  subliming  a  mixture 
of  muriate  of  ammonia  and  chalk,  or  a  mixture  of  the  well- 
known  salt  of  hartshorn  with  animal  charcoal  (see  Chap.  II, 


CARBONATE  OF  POTASH.  — OF  SODA.     281 

page  124).  From  these  mixtures  it  is  produced  in  semi-transpa- 
rent lumps,  which  have  a  pungent,  penetrating  taste  and  smell, 
and  are  used  in  medicine. 

A  mixture  of  carbonate  of  ammonia  and  rancid  mineral  oil  or 
fat  is  obtained  by  dry  distillation  of  animal  substances,  such  as 
bones,  horns,  hoofs,  dried  manure,  &c,  (all  of  which  contain, 
as  we  shall  see  hereafter,  a  great  proportion  of  nitrogen). 
The  product  thus  obtained  is  called  salts  of  hartshorn,  and  is  a 
yellowish  brown  salt  of  a  penetrating,  highly  disagreeable 
smell,  which  is  used  in  medicine. 

2.      Carbonate  of  Potash. 

Chemical  Composition  :    1  equiv.  of  carbonic  acid  =  22 
1     do.  of  potash  =  48 


Consequently,  chem.  equiv.  of  carbonate  of  potash  =  70. 

§  277.  This  salt  is  obtained  from  the  ashes  of  plants 
growing  remote  from  the  sea-shore,  which  for  this  purpose 
are  dissolved  in  water,  boiled,  and  afterwards  calcined. 
It  constitutes  the  pot-ash  and  pearl-ash  of  commerce,  and 
is  a  solid,  white  mass,  which  is  easily  soluble  in  water, 
melts  at  a  red  heat,  and  evaporates  at  a  white  heat.  Its 
taste  is  alkaline,  but  very  little  caustic.  It  is  extensively 
used  in  the  manufactory  of  soap,  in  bleaching  and  dyeing, 
and  in  glass  making. 

If  carbonic  acid  gas  is  passed  through  a  solution  of  carbon- 
ate of  potash,  a  bi-carbonate  of  potash  is  obtained,  which  crys- 
talizes  in  great  colorless  crystals,  and  tastes  yet  a  little  alka- 
line, but  not  caustic.  By  boiling  and  heating  it  part  of  the  acid 
is  given  off,  arid  the  product  is  a  ses^wi-carbonate  of  potash. 

3.     Carbonate  of  Soda. 

Chemical  Composition  :    1  equiv.  of  carbonic  acid  =  22 
1     do.  of  soda  =32 


Consequently,  chem.  equiv.  of  carbonate  of  soda  =  54. 

§  278.  Carbonate  of  soda  (soda-salt)  is  found,  in  a 
state  of  solution,  in  some  minerals.  It  is  prepared  on  a 
large  scale,  from  the  ashes  of  plants  which  grow  near  the 
sea-shore,  in  a  manner  similar  to  that  in  which  carbonate 

24* 


282          CARBONATE   OP   MAGNESIA   —OF    LIME. 

of  potash  is  obtained  from  the  ashes  of  plants  growing  re- 
mote from  it.  (§  277).  It  is  a  white,  solid  mass,  similar 
to  carbonate  of  potash,  only  its  taste  is  milder,  and  it  is 
more  easily  fusible  in  water.  It  forms  colorless,  transpa- 
rent crystals  which  effloresce  and  undergo  aqueous  fusion. 
It  is  used  in  the  manufactory  of  glass,  in  dyeing,  in  calico- 
printing,  and  in  medicine. 

The  bi-carbonate  and  sesqui-carbonate  of  soda  are  obtained 
from  the  carbonate  in  the  same  manner  in  which  the  bi-and  ses- 
qui-carbonate of  potash  are  respectively  obtained  from  carbon- 
ate of  potash.  The  sesqui-carbonate  of  soda  is  an  abundant 
product  of  nature,  occurring  particularly  in  Egypt,  Hungary, 
and  South  America. 

4.     Carbonate  of  Magnesia. 

Chemical  Composition :      1  equiv.  of  carbonic  acid  =  22 
1     do.          of  magnesia  =  20 

Consequently,  chern.  equiv.  of  carbonate  of  magnesia  =  42. 

§  279.  This  salt  occurs  in  large  lumps  in  the  East 
Indies.  It  is  also  (though  not  so  pure)  obtained  by  adding 
carbonate  of  potash  to  sulphate  of  magnesia,  at  a  high  tem- 
perature. It  is  a  white,  inodorous,  tasteless  powder,  which 
is  but  sparingly  soluble  in  water,  but  readily  dissolved  by 
the  acids.  When  a  solution  of  it  in  dilute  carbonic  acid, 
is  suffered  to  evaporate,  it  crystalizes  in  small  prisms, 
which  effloresce,  are  easily  soluble  in  water,  and  are  ex- 
tensively used  in  medicine.  Sir  Humphrey  Davy,  mixed 
this  salt  with  flour  to  make  the  bread  lighter  and  healthier 
(40  grains  of  carbonate  of  magnesia  to  one  pound  of  bread). 

5.     Carbonate  of  Lime. 

Chemical  Composition:   1  equiv.  of  carbonic  acid  =  22 
I     do.  of  lime  =  28 


Consequently,  chem.  equiv.  of  carbonate  of  lime  =  50. 

§  280.  Carbonate  of  lime  occurs  native  in  huge 
masses,  forming  whole  chains  of  mountains.  It  is  either 
crystalized,  as  spar,  or  in  a  crystaline  state,  as  white  mar- 


CARBONATE    OP    BARYTA.  — OF    LEAD.  283 

bte ;  hard,  as  lime-stone,  or  earthy,  as  chalk.  It  is  also 
found  in  the  animal  kingdom,  in  the  shells  of  oysters, 
snails,  eggs,  &c.  That  which  is  prepared  by  art  is  obtain- 
ed from  a  solution  of  burnt  oyster-shelis  in  muriatic  acid. 
It  consists  generally  of  a  white  powder,  which  is  inodor- 
ous, tasteless  and  insoluble  in  water  ;  but  soluble  in  very 
dilute  carbonic  acid,  forming  with  it  bi-carbonate  of  lime. 
By  a  red  heat  it  becomes  decomposed,  gives  off  its  acid, 
and  becomes  changed  into  lime.  (This  explains  the 
burning  of  chalk  and  lime-stone  to  lime).  The  stones 
used  in  lithography  are  also  a  carbonate  of  lime. 

6.     Carbonate  of  Baryta. 

Chemical  Composition :    1  equiv.  of  carbonic  acid  =    22 
1     do.  of  baryta  =    78 

Consequently,  chem.  equiv.  of  carbonate  of  baryta  =  100. 

§  281.  Carbonate  of  baryta  is  likewise  a  product  of 
nature,  and  occurs  as  a  distinct  fossil  in  England  (in  the 
the  counties  of  Lancashire,  Durham,  Cumberland,  &c), 
in  Hungary,  and  particularly  in  Siberia.  It  crystalizes  in 
semi-transparent,  greyish  white,  sometimes  greenish  prisms, 
but  is  also  precipitated  as  a  white,  insoluble  powder,  from 
a  solution  of  baryta  water,  and  carbonate  of  potash.  It 
has  neither  taste  nor  smell  ;  but  is  very  poisonous.  Mixed 
with  charcoal  and  exposed  to  a  red  heat ;  it  becomes  de- 
composed, whereby  carbonic  acid  is  given  off,  and  caustic 
baryta  remains. 

7.     Carbonate  of  Lead. 

Chemical  Composition  :    1  equiv.  of  carbonic  acid  =    22 
1     do.     of  oxide  of  lead  =  !  12 


Consequently,  chem.  equiv.  of  carbonate  of  lead  =  134. 

§  282.  This  is  a  metallic  ore,  commonly  called  white 
lead.  It  is  manufactured  on  a  large  scale  by  exposing 
sheet  lead  to  the  action  of  vinegar.  In  modern  times  it  has 
also  been  obtained  as  a  precipitate,  by  adding  carbonate 
of  potash  (§  277)  to  nitrate  of  lead.  It  has  a  beautiful 


284      CARBONATE  OF  IRON.  — OF  COPPER. 

white  color,  is  insoluble  in  water,  but  readily  dissolves  in  a 
solution  of  carbonic  acid.  It  is  extensively  used  as  a 
paint,  on  which  account  it  is  an  important  article  of  com- 
merce. 

8.     Carbonate   of  Iron. 

Chemical  Composition :   1  equiv.  of  carbonic  acid  =  22 
1  equiv.  of  protoxide  of  iron  =  36 

Consequently,  chein.  equiv.  of  carbonate  of  iron  =  58. 

§  283.  This  salt  occurs  as  a  natural  product  in  some  of 
the  iron  ores,  but  may  also  be  obtained  as  a  precipitate 
from  a  solution  of  sulphate  of  iron  with  carbonate  of  pot- 
ash. The  native  carbonate  forms  white  crystals  ;  that 
which  is  produced  by  art  is  a  greenish  white  powder, 
which  in  contact  with  the  atmosphere  gradually  loses  its 
acid,  and  changes  its  color  into  brown.  It  is  inodorous, 
tasteless,  and  insoluble  in  water,  and  is  used  in  the  manu- 
factory of  steel,  and  in  the  preparation  of  some  artificial 
mineral-waters. 

'*;fi   9.     Carbonate  of  Copper. 

Chemical  Composition  :    1  equiv.  of  carbonic  acid  =   22 

1  equiv.  of  per-oxide  of  copper  =    80 

to  which  is  added  1  equivalent  of  water  =     9 

Consequently,  chem.  equiv.  of  carbonate  of  copper  =111. 

§  284.  This  carbonate  occurs  likewise  native,  as 
Malachite,  a  beautiful  green  mineral,  which  is  principally 
used  in  the  preparation  of  green  and  blue  pigments.  It 
is  also  obtained,  as  a  precipitate,  from  a  mixture  of  sul- 
phate of  copper  with  carbonate  of  potash.  The  green 
substance  which  is  formed  in  copper  and  bronze  vessels, 
when  exposed  to  a  damp  atmosphere,  is  a  carbonate  of  the 
same  metal. 

G.     PHOSPHATES. 
§  285.       General  characteristics    of   the   Phosphates. 


PHOSPHATE    OF    AMMONIA. -OF    SODA. 


285 


The  salts  belonging  to  this  class  are  formed  by  the  union 
of  phosphoric  acid  with  the  different  salifiable  bases,  and 
may  easily  be  marked  by  the  following  characteristics  : 

1.  They  are  not  decomposed  by  a  red  heat,  but  melt  at 
higher  temperatures. 

2.  They  are,  with   the  exception  of  the  phosphates  of 
potash,  soda,  and  ammonia,  but  sparingly  soluble  in  water. 

3.  They    are    all    dissolved    without   effervescence,  by 
phosphoric  and  nitric  acid,  from  which  they  may  again  be 
precipitated  by  an  addition  of  ammonia. 

1 .     Phosphate  of  Ammonia. 


Chemical  Composition : 


I  equiv.  of  phosphoric  acid  =  28 
1     do.  of  ammonia  =  17 


Consequently,  chem.  equiv.  ofphosphate  of  ammonia=  45. 

5  286.  This  salt  occurs  in  some  of  the  liquids  of  car- 
nivorous animals,  and  rnay  be  prepared  from  carbonate  of 
ammonia  and  phosphate  of  lime  .  It  has  a  pungent  but 
cooling  taste,  and  is  easily  soluble  in  water.  It  is  used 
for  the  preparation  of  phosphoric  acid. 

2.     Phosphate  of  Soda. 


Chemical  Composition : 


1  equiv.  of  phosphoric  acid  =  28 
1      do.  of  soda  =  32 


Consequently,  chem.  equiv.  of  phosphate  of  soda  =60. 

§  287.  Phosphate  of  soda  occurs  likewise  in  animal 
liquids.  It  may  be  obtained  by  neutralizing  phosphoric 
acid  with  carbonate  of  soda;  crystalizes  in  colorless, 
transparent  rhombs,  has  a  cold,  saline  (not  bitter)  taste, 
effloresces  in  contact  with  the  atmosphere,  and  when  ex- 
posed to  an  intense  heat,  undergoes  first  aqueous  and  af- 
terwards igneous  fusion  (see  §  235).  Combined  with 
phosphate  of  ammonia  (§  286),  it  forms  a  salt  with  double 
bases,  known  by  the  name  of  microcosmic  salt,  which  may 
be  procured  by  dissolving  muriate  of  ammonia  and  phos- 
phate of  soda  in  boiling  water,  and  is  used  instead  of  borax 


286  PHOSPHATE    OF    LIME. 

(§  120)  for  a  variety  of  technical  purposes.     Phosphate  of 
soda  is  also  used  in  medicine. 

3.     Phosphate  of  Lime. 

Chemical  Composition :    1  equiv.  of  phosphoric  acid  =  28 

1     do.  of  lime  =  28 

to  which  is  added  2  equiv.  of  water  (each  =  9)  =  18 

Consequently,  chem.  equiv.  of  phosphate  of  lime  =  74. 

§  288.  Phosphate  of  lime  is  a  principal  ingredient  of 
the  bones  of  animals,  but  is  also  contained  in  other  solids, 
and  in  some  of  the  liquids  of  their  bodies,  as,  for  instance, 
in  milk,  in  the  white  of  eggs,  &,c.  It  is  generally  pro- 
cured by  the  calcination  of  bones,  and  consists  of  a  greyish 
white  powder,  which  soon  dries  to  a  hard  lump.  Jt  is 
easily  soluble  in  nitric,  muriatic,  and  phosphoric  acid 
and  melts,  when  heated,  to  a  mass  which  bears  a  strong 
resemblance  to  porcelain.  It  is  used  for  cleansing  brass, 
as  a  tooth  powder,  and  in  the  manufactory  of  milk-glass 
and  porcelain. 

Bi-phosphate  of  lime  is  obtained  from  a  solution  of  phos- 
phate of  lime  in  any  strong  mineral  acid.  It  forms  crystals  of 
a  lamellar  texture,  has  a  sour  taste,  deliquesces,  is  easily  solu- 
ble in  water,  and  is  used  in  the  manufactory  of  phosphorus 
and  phosphoric  acid. 

The  phosphites  created  by  the  union  of  phosphorus  acid 
with  the  different  salifiable  bases  are  here  omitted  j  be- 
cause they  are  of  very  little  application  in  the  arts  or  in  medi- 
cine. 


H.     CHROMATES. 

§  289.  Properties  of  the  Chromates.  The  salts  form- 
ed by  chromic  acid  in  combination  with  the  bases  have  all 
a  yellow  orange-color,  and  afford,  when  mixed  with  potash 
or  soda  through  the  influence  of  the  blow-pipe,  (see 
chemical  apparatus,  page  26),  a  beautiful,  green-colored 
glass. 


CHROMATE   OF    POTASH.  — OF   LEAD.  287 

1.     Chr ornate  of  Potash. 

§  290.  This  salt  is  manufactured  on  a  large  scale  in 
Manchester  and  London,  by  heating  one  of  the  iron  ores, 
called  chromate  of  iron,  with  an  equal  weight  of  nitre  and 
carbonate  of  potash.  1  equivalent  of  the  chromic  acid 
which  is  thus  formed,  combines  with  1  equivalent  of  pot- 
ash to  a  salt  which  crystalizes  in  yellow,  six-sided  prisms, 
has  a  bitter,  disagreeable  taste,  melts  at  a  red  heat  and  be- 
comes green.  It  is  used  in  the  preparation  of  chromic 
acid,  in  the  manufactory  of  several  paints  and  pigments, 
in  calico  printing,  &/c. 

2.     Chromate  of  Lead. 

§  291.  1  equivalent  of  chromic  acid,  combined  with 
1  equivalent  of  lead,  occurs  crystalized  in  the  red  ore  of 
lead.  It  is  semi-transparent,  and  of  a  beautiful  red  (sel- 
dom yellow)  color.  It  may  be  produced  by  art,  by  pre- 
cipitating nitrate  of  lead  with  chromate  of  potash  (§  290). 
It  is  a  tasteless,  inodorous  powder,  which  is  in  soluble  in 
water  and  unchangeable  by  light  or  air.  It  may  be  used  as 
a  pigment,  in  calico-printing  and  in  oil-painting. 

3.     Chromate  of  Mercury. 

§  292.  Chromate  of  mercury  is  obtained  by  precipi- 
tating nitrate  of  mercury  with  chromate  of  potash.  It  pos- 
sesses a  beautiful  orange-color,  is  insoluble  in  water,  but 
readily  dissolved  in  nitric  acid,  and  is  used  as  a  red  pig- 
ment. 

t.     ARSENIATES  AND  ARSENITES. 

§  293.  Characteristics  of  the  Arseniates  and  Arsenites. 
These  salts  possess  the  following  general  properties  : 

1.  They  are  insoluble  in  water  (the  arseniates  of  potash, 
soda,  and  ammonia  alone  excepted). 

2.  They  are  all  decomposed  when  heated  with  charcoal 

3.  They  are  all  readily  dissolved  in  arsenic  and  nitric 
acid. 


288     ARSENITE  OF  POTASH. -OF  COBALT. 

1.  Arsenite  of  Potash. 

§  294.  This  combination  of  arsenious  acid  with  potash 
is  produced  by  boiling  until  neutralization  a  solution  of 
carbonate  of  potash  with  powdered  arsenious  acid.  The 
salt  thus  obtained  deliquesces  so  easily  that  it  has  not  as 
yet  been  obtained  in  crystals.  A  thick  solution  of  it  is 
yellow,  has  a  disagreeable  smell,  and  is  highly  poisonous. 
It  is  used  in  calico-printing,  and  in  small  quantities  even 
in  medicine. 

2.  Arsenite  of  Cobalt. 

§  295.  Arsenite  of  cobalt  occurs  as  a  red  ore  of  cobalt, 
or  may  be  prepared  by  the  action  of  double  affinity  (see  In- 
troduction XVIII),  from  arsenite  of  potash  (§  294)  on  any 
salt  of  cobalt.  (The  cobalt  of  the  salt  separates  the  arsen- 
ious acid  from  the  potash  and  combines  with  it  to  a  neu- 
tral salt).  It  is  a  red  powder  which  gives  a  blue  color  to 
glass  or  clay,  is  decomposed  by  heat,  and  dissolves  in  am- 
monia to  a  liquid  of  a  dark  red  color. 

K.     CYANITES  AND  FULMINATES. 

§  296.  Cyanites  and  Fulminates.  We  have  already 
spoken  of  the  combinations  of  cyanogen  with  oxygen 
(Chap.  II,  §  89),  the  products  of  which  are  cyanous  and 
fulminic  acid. 

Fulminic  acid  (only  discovered  in  1824)  occurs  no 
where  in  nature,  but  may  be  formed  by  mixing  nitrate  of 
mercury  or  silver  with  alcohol  at  a  high  temperature.  Al- 
cohol and  nitric  acid  are  given  off,  and  the  remaining  ni- 
trogen, oxygen,  and  carbon  form  fulminic  acid.  This, 
however,  is  mixed  with  other  substances,  and  all  attempts 
to  isolate  the  acid,  or  to  obtain  it  in  a  pure  state  have 
hitherto  failed.  The  salts  of  this  acid,  which  are  called 
fulminates,  have  the  remarkable  property,  not  possessed  by 
the  cyanates  or  cyanites,  of  detonating  and  exploding  at 
the  slightest  friction,  or  in  contact  with  concentrated  sul- 
phuric or  nitric  acid.  These  salts  are  now  used  in  the 


RECAPITULATION.  289 

manufactory  of  percussion  caps,  instead  of  the  locks  of  fire- 
arms. 

The  cyanous  acid  forms  with  the  different  bases  cyanites, 
which,  by  heat,  are  easily  decomposed  into  ammonia  and 
carbonic  acid. 

REMARK.  The  cyanic  acid  is  composed  of  the  same  ele- 
ments and  united  in  the  same  proportion  as  those  of  fulminic 
acid,  and  yet  the  properties  of  its  salts  (the  fulminates)  are 
entirely  different  from  those  of  the  fulminates  (formed  by  ful- 
minic acid).  The  reason  of  this  difference  is  not  sufficiently 
accounted  for. 

We  might  speak  of  the  bromates,  sodates,  hydro-brom- 
ates,  and  almost  an  infinite  number  of  other  salts;  but 
we  have  proposed  only  to  treat  of  those  which  are  of  fre- 
quent application  in  common  life,  and  with  which  it  is  ab- 
solutely necessary  to  be  acquainted,  to  understand  even 
the  most  ordinary  processes  of  the  arts. 


RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles 
contained  in  Chapter  IV. 

A.     QUESTIONS    ON  THE    GENERAL    REMARKS   ON   THE 
SALTS. 

[§  227.]  What  two  elements  are  by  far  the  most  pow- 
erful agents  in  nature  1  What  is  the  product  of  their 
union  ?  What  are  all  bodies  in  relation  to  oxygen  and 
hydrogen  1 

Give  examples. 

[§  228.]  What  are  the  most  remarkable  products  ob- 
tained by  the  combination  of  oxygen  and  hydrogen  with 
other  substances  ?  What  is  the  body  called  which  in  com- 
bination with  oxygen  or  hydrogen  forms  an  acid  1  What 
is  the  oxygen  or  hydrogen  called  ?  What  is  the  acidifying 

25 


RECAPITULATION 

principle  in  nitric  acid  1     What  is  the  acidifying  principle 
in  muriatic  acid? 

What  is  the  electro  positive,  and  what  the  electro-negative 
factor  in  an  acid  ? 

[§  229.]  What  are  those  acids  called  into  whose  com- 
position hydrogen  enters  as  the  acidifying  principle  1 
What  acids  belong  to  this  class? 

What  do  many  other  acids  require  for  their  liquid  form  ? 
What  are  those  acids  called  ?  What  word  have  they  pre- 
fixed to  their  names  ?  What  are  those  acids  called  in 
which  water  does  not  enter  as  an  essential  ingredient? 

[§  230.]  What  class  of  bodies  do  the  acids  form  when 
combined  with  those  substances  called  bases  ?  How  then 
is  a  salt  defined  ? 

What  occurs  when  a  salt  is  decomposed  by  the  agency 
of  the  galvanic  pile?  What  do  we  infer  from  this  fact? 

What  is  the  opinion  of  some  philosophers  in  reference  to  all 
chemical  phenomena  ?  By  whom  is  this  theory  supported  ? 
Can  you  state  any  facts  which  may  serve  to  corroborate  this 
theory  ? 

Explain  experiment  I,  represented  in  Fig.  CXV. 

How  is  this  phenomenon  accounted  for  by  the  electric  attrac- 
tion of  the  battery  ? 

Explain  experiment  II,  represented  in  Fig.  CXVI. 

What  do  we  see  from  this  experiment  ? 

What  takes  place,  if,  in  your  last  experiment,  a  solution  of 
sulphate  of  soda  is  placed  in  the  cup  connected  with  the  nega- 
tive or  copper  pole,  and  in  the  other  two  a  solution  of  red  cab- 
bage ?  Is  the  result  different  if  the  middle  cup  be  filled  with 
an  alkaline  solution  ? 

Now  what  do  these  experiments  prove  ? 

[§  231.]  What  sort  of  bodies  are  all  the  salifiable  ba- 
ses with  the  exception  of  ammonia  ?  Are  organic  bodies 
capable  of  becoming  salifiable  bases  ?  How  are  the  bases 
therefore  divided  ?  What  bases  in  the  mineral  kingdom 
are  easily  soluble  in  water  ?  Which  are  not  easily  soluble  ? 
Which  bases  are  insoluble  in  water  ?  How  are  the  organic 
bases  again  divided  ? 

Why  may  the  salts  be  considered  as  quarternary  combina- 
tions of  the  elements  ? 


OF    CHAPTER    IV.  291 

[§  232.]  What  does  each  of  the  acids  form,  in  union 
with  the  salifiable  frases  ?  After  what  are  the  different 
salts  thus  produced,  commonly  denominated  1  Into  what 
is  the  denomination  of  the  acid  in  ic  changed?  Into  what 
is  that  terminating  in  ous  changed  ?  Give  examples. 
What  do  you  call  the  salt  which  arises  from  the  combination 
of  sulphuric  acid  with  soda  1  What,  that  which  is  formed 
by  sulphurows  acid  with  ammonia  1 

Is  the  nomenclature  of  salts  advantageous  or  not  ?  What 
does  the  appellation  of  each  salt  show  ? 

[§  233.]  How  have  the  different  salts  yet  been  divid- 
ed. What  do  you  understand  by  a  neutral  salt  ?  What 
by  a  sour ;  what  by  a  basic  salt  ? 

[§  234.]  What  do  all  salts  which  are  obtained  in  form 
of  crystals  contain?  What  is  the  water  called,  which  is 
mechanically  entangled  ?  What  that  which  is  chemically 
combined  ?  What  do  all  salts  which  contain  water  me- 
chanically entangled,  when  thrown  into  fire?  What  is 
this  owing  to  ?  Does  the  same  happen  with  the  salts  which 
contain  water  as  a  chemical  ingredient? 

[§  235.]  What  do  some  salts  lose  at  common  tempera- 
tures of  the  atmosphere  1  What  are  they  then  said  to  do  ? 
What  do  you  understand  by  the  phenomenon  of  deliques- 
cence ?  What  do  you  call  the  process  by  which  a  salt 
is  melted  by  heat,  without  being  decomposed  ?  What, 
that,  when  a  salt  melts  in  its  own  water,  if  the  solving 
power  of  the  water  is  increased  by  heat. 

Questions  on  Crystalography. 

What  takes  place  when  a  body,  from  a  state  of  solution, 
is  converted  into  a  solid,  so  that  its  particles  are  capable  of 
following  their  own  mutual  attractions?  What  is  it  then 
called  ?  What  important  discovery  did  Haiiy  make,  with  re- 
gard to  the  division  of  crystals  ?  What  peculiar  geometrical 
forms  did  he  discover  were  no  longer  divisible  without  fracture? 
What  is  this  geometrical  form  called,  which  is,  as  it  were,  the 
nucleus  of  the  crystal  ?  What  is  the  shape  called,  which  the 
crystal  has  before  the  division  ? 

To  how  many  regular  geometrical  solids  are  the  primitive 
forms  of  all  crystals  reducible  ?  (Call  the  different  geometri- 


292  RECAPITULATION 

« 

cal  solids,  represented  in  Figs.  CXVII,  CXVIII,  CXIX,  CXX, 
CXXI,  CXXII,  CXXIII,  CXXIV). 

To  what  three  solids  are  these  six,  again  reducible  by  math- 
ematical division  ?  What,  therefore,  is  the  opinion  of  some 
philosophers  respecting  the  primitive  form  of  crystals  ?  What 
are  these  three  solids  called? 

By  what  means  may  any  prism  whatever  be  divided  into  tri- 
angular prisms  ?  How  may  the  rhombic  dodecahedron  be 
formed  by  integrant  cubes?  (Explain  Fig.  CXXVIII). 
What  is  Dr  Wollaston's  theory  respecting  the  integrant 
molecules  of  crystals  ?  (Explain  Figs.  CXXIX,  —  CXXXIV). 

In  what  respect  is  this  theory  superior  to  Hauy's  ? 

[§  236.]     What   are  the  names  of  the  principalsalts 
according  to  their  nomenclature  after  the  acids  ? 

A.     QUESTIONS  ON  THE  NITRATES. 

[§  237.]  What  are  the  principal  properties  of  the  ni- 
trates ? 

[§  238.]  What  is  the  chemical  composition  of  nitrate 
of  potash  ?  Where  does  this  salt  occur  ?  By  what  means 
may  it  be  obtained  artificially  ? 

How  is  nitre  produced  in  France  and  Germany  for  the  man- 
ufacture of  gunpowder  ? 

[§  239.]  What  are  the  principal  properties  of  nitre  ? 
In  what  consists  the  chief  use  of  nitre  ? 

[§  240.]  What  is  the  most  remarkable  application  of 
nitre  ?  Of  what  ingredients  does  gunpowder  generally 
consist  1 

What  are  the  properties  of  good  gunpowder  ? 

At  what  temperature  does  gunpowder  ignite  ?  To  what 
is  its  subsequent  expansion  and  propelling  power  owing  ? 

[§  241.]  What  is  the  chemical  composition  of  nitrate 
of  soda?  Where  does  this  salt  occur?  How  may  it  be 
produced  artificially?  What  are  its  properties?  For 
what  purposes  is  it  used  ? 

[§  242.]     What  is  the  chemical  composition  of  nitrate 


OF    CHAPTER    IV.  293 

of  ammonia?     How  is  this  salt  produced?     What  are  its 
properties  1 

[§  243.]  What  is  the  chemical  composition  of  nitrate 
of  lime?  Where  does  it  occur?  How  may  it  be  produ- 
ced ?  What  form  does  it  assume  by  crystalization  ?  What 
are  its  properties  1 

[§  244.]  What  is  the  chemical  composition  of  proto- 
nitrate  of  mercury  1  What,  that  of  per-nitrate  of  mercury  ? 

How  is  the  proto-nitrate  of  mercury  obtained  ?  How  is 
the  per-nitrate  obtained  ?  For  what  purposes  are  both 
nitrates  used  ? 

[§  245.]  What  is  the  chemical  composition  of  nitrate 
of  silver?  By  what  other  name  is  this  salt  known,  when 
fused  and  cast  into  small  bars  ?  How  is  it  obtained  ? 
What  are  its  properties  ? 

How  is  nitrate  of  silver  used  as  indelible  or  marking  ink  ? 

[§  246.]  What  is  the  chemical  composition  of  nitrate 
of  lead?  How  is  this  salt  obtained  ?  What  are  its  prop- 
erties ?  For  what  purposes  is  it  used  ? 

[§  247.]  What  is  the  chemical  composition  of  nitrate 
of  copper  ?  How  is  it  obtained  ?  What  are  its  proper- 
ties? 

B.     QUESTIONS  ON  THE  CHLORATES. 

[§  248.]  What  are  the  principal  properties  of  the 
chlorates  ? 

[§  249.]  What  is  the  chemical  composition  of  the 
chlorate  of  potash  ?  How  is  this  salt  produced  ? 

Explain  the  experiment  represented  in  Fig.  CXXXV. 

[§  250.]  What  are  the  characterizing  properties  of 
chlorate  of  potash  ?  For  what  is  it  used  ? 

How  are  instantaneous  light-matches  constructed  ?  For  what 
purposes  did  Bartholet,  a  French  chemist,  endeavor  to  use  this 
salt  ?  For  what  purposes  is  it,  nevertheless,  used  ? 

25* 


294  RECAPITULATION 

[§  251.]  What  is  the  chemical  composition  of  chlo- 
rate of  soda  ?  How  is  it  obtained  ?  What  are  its  prop- 
erties ? 

[§  252.]  What  is  the  chemical  composition  of  hydro- 
chlorate  of  ammonia  ?  What  is  this  salt  commonly  called  ? 
Where  is  it  found  1  From  what  is  it  manufactured  ?  By 
what  means  may  it  also  be  obtained  1  What  are  its  prop- 
erties ? 

C.     QUESTIONS  ON  CHLORIDES. 

[§  253.  What  property  have  all  the  salts  belonging  to 
the  class  of  chlorides? 

[§  254.]  What  is  the  chemical  composition  of  chloride 
of  lime?  How  is  this  salt  manufactured  ? 

[§  255.]  What  are  the  properties  of  chloride  of  lime  ? 
What  are  the  applications  of  chloride  of  lime? 

D.     QUESTIONS  ON  THE  MURIATES  (CHLORIDES). 

[$  256.]  By  what  properties  are  the  muriates  distin- 
guished ? 

What  different  opinions  exist  with  regard  to  the  muriates  ? 
What  is  the  chemical  composition  of  chloride  of  silver? 

[§  257.]  How  is  chloride  of  gold  prepared  ?  What 
are  its  properties  ?  For  what  purposes  is  it  used  ? 

[§  258.]  What  is  the  chemical  composition  of  chloride 
of  platinum  ?  How  is  the  double  chloride  (bi-chloride)  of 
platinum  obtained  ?  What  are  its  properties  ?  How  is  the 
simple  chloride  of  platinum  obtained? 

[§  259.]  What  is  the  chemical  composition  of  chlo- 
ride of  copper  ?  How  is  double  chloride  of  copper  obtain- 
ed ?  How  is  the  simple  chloride  of  copper  obtained  from 
the  double  chloride  ?  How  may  the  an-hydrous  chloride 
of  copper  be  obtained  ?  What  are  its  properties  ? 


OF    CHAPTER    IV. 


295 


[§  260.],  By  what  means  is  chloride  of  tin  obtained? 
What  are  its  properties  1  For  what  purposes  is  it  used  ? 

How  is  the  per-chloride  of  tin  obtained  ?  What  are  its 
properties  ?  Into  what  does  it  become  converted  when  mixed 
with  one  third  of  its  weight  of  water? 

[§  201.]  How  is  chloride  of  cobalt  produced  ?  What 
are  its  properties  ? 

For  what  may  a  weak  solution  of  chloride  of  cobalt  be  used  ? 

E.     QUESTIONS  ON  THE  SULPHATES. 

[§  262.]  By  what  characterizing  properties  are  the 
sulphates  distinguished,  as  a  class  of  salts  1 

[§  263.]  What  is  the  chemical  composition  of  sul- 
phate of  potash  ?  Where  does  this  salt  occur  ?  How  is  it 
obtained  ?  What  are  its  properties  1 

[§  264.]  What  is  the  chemical  composition  of  sulphate 
of  soda  ?  By  what  other  name  is  this  salt  yet  known  in 
medicine  ?  Where  does  it  occur  ?  By  what  means  is  it 
obtained  in  large  quantities  1  What  form  does  it  assume  by 
crystalization  1  What  are  its  properties  1  Where  is  it  used  1 

[§  265.]  What  is  the  chemical  composition  of  sulphate 
of  lime?  Where  does  it  occur?  In  what  form  does  it 
crystalize  ? 

What  are  the  properties  of  alabaster  ?  What  is  the  most 
compact  kind  of  alabaster  ? 

What  are  the  properties  of  plaster-stone  ? 

How  may  gypsum  be  produced  ?  By  what  process  does  it 
become  reduced  to  plaster  of  Paris  ?  What  are  the  uses  of 
this  salt?' 

[§  266.]  What  is  the  chemical  composition  of  sulphate 
of  magnesia  ?  In  what  is  this  salt  contained  ?  Where  is 
it  also  found  in  small  quantities  ?  By  what  means  may  it  be 
produced  by  art  ?  What  are  its  properties  ? 

[§  267.]  What  is  the  chemical  composition  of  proto- 
sulphate  of  mercury  ?  What  that  of  per-sulphate  of  mer- 
cury ?  How  is  the  per-sulphate  of  mercury  obtained  ? 


296  RECAPITULATION 

What  are  its  properties  ?     Into  what  two  salts  is  this  salt 
decomposed  by  the  agency  of  water  1     What  are  the  prop- 
erties of  the  basic  salt  ?     As  what  is  it  used  ? 
How  is  proto-sulphate  of  mercury  obtained  ? 

[§  268.]  What  is  the  chemical  composition  of  sulphate 
of  silver  ?  How  is  this  salt  obtained?  What  are  its  prop- 
erties 1 

[§  269.]  What  is  the  chemical  composition  of  per-sul- 
phate  of  copper  ?  Where  does  it  occur  ?  From  what  may 
it  be  obtained  ?  What  properties  do  the  crystals  possess 
which  it  forms  ?  For  what  purposes  are  they  used  ? 

[§  270.]  What  is  the  chemical  composition  of  sulphate 
of  iron  1  Where  is  this  salt  found  1  What  are  its  prop- 
erties ? 

[§  271.]  What  is  the  chemical  composition  of  sulphate 
of  baryta  ?  Where  is  it  found  ?  What  are  its  properties  1 

[§  272.]  What  is  the  chemical  composition  of  sulphate 
of  ammonia?  How  is  this  salt  obtained?  What  are  its 
properties  ? 

[§  273.]  What  is  the  chemical  composition  of  sulphate 
of  alumine  ?  What  sort  of  product  is  it?  How  is  it  ob- 
tained by  art  ?  What  are  its  properties  ?  With  what  sub- 
stances does  it  combine?  What  class  of  salts  does  it 
thereby  form  ?  Give  an  example. 

[§  274.]  What  two  salts  are  the  two  most  impor- 
tant kinds  of  alum  ?  What  sort  of  products  are  they  ? 
Which  of  the  two  is  met  with  in  greatest  abundance  ?  By 
what  other  means  may  they  be  obtained  ?  What  are  its 
properties  ?  How  is  burnt  alum  obtained  ? 

For  what  purposes  is  alum  used  in  the  arts  ? 

F.     QUESTIONS  ON  THE  CARBONATES. 

[§  275.]  What  are  the  general  characteristics  of  the 
carbonates  ? 

[5}  276.]     What  is  the  chemical  composition  of  carbon- 


OF    CHAPTER    IV.  297 

ate  of  ammonia  ?  What  is  the  product  of  the  combustion 
of  two  volumes  of  dry  ammonia  with  one  volume  of  car- 
bonic acid  called  1  What  properties  does  it  possess? 

By  what  name  is  the  sesqui-carbonate  (l^-carbonate)of  am- 
monia known  in  commerce  ?  How  is  it  obtained?  In  what 
shape  ?  What  properties  does  it  possess  ?  From  what  sub- 
stances is  salts  of  hartshorn  obtained  ?  What  are  its  proper- 
ties ? 

[§  277.]  What  is  the  chemical  composition  of  carbon- 
ate of  potash  ?  How  is  this  salt  obtained  ?  What  are  its 
properties  ? 

How  is  bi-carbonate  of  potash  obtained  ?  What  are  its 
properties  ?  Into  what  does  it  become  converted  by  boiling 
and  heating  ? 

[§  278.]  What  is  the  composition  of  carbonate  of  soda? 
Where  is  it  found  ?  How  is  it  prepared  by  art  ?  What 
are  its  properties  ?  What  sort  of  crystals  does  it  form  ? 
For  what  purpose  is  it  used  ? 

How  are  the  bi-carbonate  of  sesqui-carbonate  of  soda  ob- 
tained ?  What  sort  of  product  is  the  sesqui-carbonate  of  soda  ? 

[§  279.]  What  is  the  chemical  composition  of  carbon- 
ate of  magnesia?  Where  does  this  salt  occur  ?  By  what 
means  may  it  be  obtained  by  art  ?  What  are  its  properties  ? 
By  what  process  can  it  be  made  to  crystalize  ?  For 
what  purpose  did  Sir  Humphrey  Davy  use  this  salt  ? 

[§  280.]  What  is  the  chemical  composition  of  carbon- 
ate of  lime  ?  Where,  and  in  what  quantities  does  it  occur  ? 
In  what  animal  substances  is  it  also  found  ?  How  is  it 
prepared  by  art  ?  What  are  its  properties  ?  Into  what 
does  it  become  converted  by  a  red  heat  ?  What  sort  of 
compound  are  the  stones  used  in  lithography  ? 

[§  281.]  What  is  the  chemical  composition  of  carbon- 
ate of  baryta  ?  What  sort  of  product  is  it  ?  Where  does 
it  occur  ?  What  are  its  properties  ?  What  becomes  of  it 
when  mixed  with  charcoal  and  exposed  to  a  red  heat? 

[§  282.]  What  is  the  chemical  composition  of  carbon- 
ate of  lead  ?  By  what  other  name  is  this  salt  yet  known  ? 


298  RECAPITULATION 

How    is   this   compound   manufactured  ?     What   are   its 
properties  ?     For  what  purposes  is  it  extensively  used  ? 

[§  283.]  What  is  the  chemical  composition  of  carbon- 
ate of  iron  ?  Where  does  this  salt  occur  ?  How  may  it 
be  obtained  by  art  1  What  are  the  properties  of  the  natu- 
ral product  ?  What  those  of  the  product,  of  art  ? 

[§  284.]  What  is  the  chemical  composition  of  carbon- 
ate of  copper  1  Where  does  it  occur  ?  How  may  it  be 
produced  by  art  ?  Of  what  consists  the  green  substance 
formed  on  the  surface  of  copper  and  bronze  vessels  when 
exposed  to  a  damp  atmosphere  ? 

G.     QUESTIONS  ON  THE  PHOSPHATES. 

[§  285.]  What  are  the  general  characteristics  of  the 
phosphates  ? 

[§  286  ]  What  is  the  chemical  composition  of  phos- 
phate of  ammonia  1  Where  does  it  occur  ?  What  are  its 
properties  ? 

[§  287.]  What  is  the  chemical  composition  of  phos- 
phate of  soda  ?  Where  does  it  occur  ?  What  are  its 
properties  ?  What  does  it  form  in  combination  with  phos- 
phate of  ammonia  ?  How  may  microcosmic  salt  be  pro- 
duced 1 

[§  288.]  What  is  the  chemical  composition  of  phos- 
phate of  lime  1  Where  does  it  occur  ?  How  is  it  gene- 
rally produced  ?  For  what  purposes  is  it  used  ? 

How  is  the  bi-phosphate  of  lime  obtained  ?  What  are  its 
properties  ? 

H.     QUESTIONS  ON  THE  CHROMATES. 

[§  289.]  What  are  the  characterizing  properties  of 
chromates  ? 

[§  290.]  How  is  the  chromate  of  potash  manufactured 
in  Manchester  and  London?  What  are  its  properties? 
for  what  purposes  is  it  used  1 


OF    CHAPTER    IV. 


299 


[§  291.]  What  salt  does  I  equivalent  of  chromic  acid, 
combined  with  1  of  .lead,  form  1  How  may  the  same  salt 
be  produced  by  art  ?  What  are  its  properties  ? 

[§  292.]     How  is  the  chromate  of  mercury  obtained  ? 
I.     QUESTIONS  ON  THE  ARSENIATES  ARD  ARSENITES. 

[§  293.]  By  what  characteristics  are  the  arseniates  and 
arsenites  distinguished  ? 

[§  294.]  How  is  arsenite  of  potash  produced  ?  What 
are  its  properties  ?  For  what  is  it  used  ? 

[§  295.]  Where  does  arsenite  of  cobalt  occur  ?  What 
are  its  properties  ? 

K.     QUESTIONS  ON  THE  CYANITES  AND  FULMINATES. 

[§  296.]  Does  fulminic  acid  occur  in  nature  in  its 
simple  form  ?  How  then  may  it  be  produced  ?  What 
are  the  salts,  formed  by  this  acid  in  combination  with  the 
different  salifiable  bases  called?  What  remarkable  prop- 
erty do  all  these  salts  possess  ?  For  what  particular  pur- 
pose are  these  salts  now  used  ? 

What  kind  of  salts  does  cyanous  acid  form  when  combined 
with  the  different  salifiable  bases  ? 

Of  what  elements  is  cyanic  acid  composed  ? 


300  GENERAL    REMARKS 


CHAPTER    V. 

VEGETABLE  CHEMISTRY. 

General  Remarks  on  the  Difference  between   Organic  and 
Inorganic  Matter. 

§  297.  In  animated  nature — plants  and  animals  —  the 
elements  of  matter  seem  to  obey  different  laws  from  those 
to  which  they  are  subjected  in  dead  matter  ;  the  products 
of  their  combinations  bearing  little  resemblance  to  those 
which  are  obtained  in  inorganic  chemistry.  Every  living 
body  may  be  considered  as  a  laboratory,  in  which  a  varie- 
ty of  chemical  processes  serve  to  support  life,  in  such  a 
manner  that  from  a  simple  atom,  it  is  gradually  developed 
to  its  highest  perfection  ;  after  which  these  processes  begin 
to  be  carried  on  more  slowly,  and  finally  cease  entirely. 
From  that  moment  the  body  obeys  all  the  laws  of  inani- 
mate matter.  Such  is  the  life  and  death  of  every  plant  and 
animal.  The  time  from  the  beginning  to  the  cessation  of 
life  (death)  is  various  ;  but  all  bodies  endowed  with  life,  in 
whatever  shape  they  may  appear  to  us,  go  through  the  two 
periods  of  gradual  perfection  and  decay. 

^  298.  Difference  between  organic  and  inorganized 
matter.  The  difference  between  organic  and  inorganic 
nature  consists,  therefore,  principally  in  this  :  The  organ- 
ized body  has  a  dejinite  beginning  and  development,  after 
which  it  is  subject  to  decay  and  death  ;  inorganic  matter, 
on  the  contrary,  continues  to  exist  (although  sometimes  in 
different  shapes)  in  whatever  situation  it  may  be  placed. 


ON   ORGANIC    AND    INORGANIC    BODIES.          301 

It  is  true,  the  inorganic  elements  of  plants,  and  elements 
(with  which  we  shall  presently  become  acquainted)  are  not 
perishable  ;  but  the  particular  nature  of  these  bodies  is,  through 
death,  irrecoverably  destroyed,  and  returns  no  more.  The  life 
of  the  plant  or  animal  is,  consequently,  not  seated  in  the  or- 
ganic elements  ;  but  in  something  higher,  in  a  directing  agent, 
which  is  altogether  different  from,  and  superior  to  chemical 
affinity,  or  any  other  attribute  of  matter.  This  inconceivable 
agent  —  the  vital  principle  of  nature  —  is,  by  the  divine  wisdom 
of  the  Creator,  distributed  throughout  our  globe  with  such  won- 
derful diversity,  and  so  eminently  well  calculated  for  the  sup- 
port of  man,  that  the  destroyed  organization  of  one  being  gives 
birth  and  support  to  another ;  by  which  means  they  are  able 
to  succeed  eacli  other  with  infinite  order  and  regularity ;  each 
fulfilling  the  end  for  which  it  was  created. 

§  299.  In  inorganic  chemistry,  we  are  generally  able 
to  produce  substances  from  their  elements  —  we  can  pro- 
duce water  from  oxygen  and  hydrogen,  the  acids  from 
a  combination  of  the  acidifying  principle  with  the  radicals, 
the  salts  from  the  acids  and  the  salifiable  bases ;  —  but 
this  is  totally  impossible  with  regard  to  plants  or  animals. 
No  one  has,  as  yet,  succeeded,  and  certainly  never  will 
succeed,  to  form  a  plant  or  an  animal  from  its  chemical 
elements.  These  bodies  need  even  for  their  support, 
products  of  organized  matter,  as  proper  materials  for  the 
chemical  processes  subservient  to  their  existence.  The 
vegetable  creation  of  one  year  subsists  on  the  residue 
of  vegetable  matlers  from  the  preceding  year  ;  grass-eating 
animals  need  plants,  carnivorous  animals  meat  of  other  an- 
imals, for  their  nutriment,  or  food. 

§  300.  Organs  —  origin  of  the  appellation  of  organized 
bodies.  The  chemical  processes  of  plants  and  animals 
take  place  in  certain  vessels  which  seem  to  be  created  for 
that  purpose.  These  vessels  are  called  organs,  whence 
the  bodies  themselves  are  said  to  be  organized. 

Of  the  manner  in  which  these  processes  are  carried  on,  we 
are,  with  a  few  exceptions,  almost  entirely  ignorant.  Neither 
do  we  know  if  the  different  elements,  which  we  have  discov- 
ered in  plants  and  animals,  are  actually  chemically  combined 
with  each  other,  or  whether  they  exist  in  them  only  in  a  state 
of  mixture. 

26 


302  GENERAL    REMARKS 

§  301.  The  products  of  vegetables  which  are  used  in 
domestic  economy  and  in  the  arts,  are  either  situated  in 
particular  organs,  or  are  diffused  throughout  the  whole 
plant.  When  they  are  seated  in  particular  organs,  (as, 
for  instance,  in  the  root,  stalk,  leaves,  husk,  seeds,  &c), 
they  may  easily  be  collected  ;  but  when  they  are  diffused 
throughout  the  whole  plant,  certain  processes  —  such  as 
washing,  drying,  distilling,  &c,  —  are  required  to  separate 
them  from  the  substances  with  which  they  are  mixed. 
More  than  thirty  different  vegetable  products  have  in  this 
manner  been  obtained  ;  the  most  important  of  which  we 
shall  speak  of  in  the  course  of  this  treatise. 

§  302.  Immediate  ingredients  of  Plants.  The  imme- 
diate ingredients,  which  are  obtained  by  the  chemical 
analysis  of  plants,  are 

1st.  Certain  gaseous  substances,  such  as  oxygen,  hydro- 
gen, nitrogen,  carbonic  acid  gas,  &c.  These  substances 
have  already  been  described  in  the  preceding  chapters. 

2d.  Substances  which  partake  more  or  less  of  the  liquid 
state.  To  these  belong  mucilage,  vegetable  extract, 
resin,  &-c. 

3d.  Solid  substances,  as,  for  instance,  woody  fibre,  fa- 
rina, fruit,  &c. 

§  303.  The  liquid  and  solid  parts  of  plants  may  again 
be  decomposed  by  the  action  of  water,  the  acids,  and  the 
oxides  of  the  mineral  kingdom,  or  by  exposure  to  a  high 
heat.  The  elements  resulting  from  their  decomposition, 
which  may  be  considered  as  the  more  remote  ingredients 
of  plants  (see  Introduction,  VII),  are  either  entirely  com- 
bustible^ that  is,  such  as  become,  by  heat,  entirely  con- 
verted into  gases,  or  Jixed  vegetable  alkalies,  which,  when 
ignited  and  submitted  to  the  highest  temperatures,  leave 
still  a  certain  quantity  of  ashes,  which  is  no  longer  reduci- 
ble by  heat.* 

For  an  illustration  of  what  has  just  been  advanced,  we  will 
give  but  two  examples  :  The  juice,  which  is  the  first  liquid 

*  This  property  they  share  with  some  of  the  oxides  and  salts ; 
hence  the  name  vegetable  alkali. 


ON    ORGANIC   AND  INORGANIC    MATTER.         303 

ingredient  of  grapes,  may  be  decomposed  into  mucilage,  sugar, 
extract,  coloring  matter,  tanning  principle,  and  vegetable  acid. 
Farina,  which  is  the  immediate  ingredient  of  wheat,  may  be 
further  reduced  to  starch,  sugar,  mucilage  and  woody  fibre,  veg- 
etable extract,  oxide,  and  salt.  These  are,  therefore,  the  more 
remote  ingredients  of  wheat. 

A  knowledge  of  both  kinds  of  ingredients,  but  more  es- 
pecially of  the  combustible  ones,  is  indispensable  to  a  cor- 
rect understanding  of  the  nature  of  plants,  as  well  as  their 
application  to  chemical,  technical  and  medicinal  purposes. 

§  304.  But  the  more  remote  ingredients  of  vegetables, 
decomposed  into  their  ultimate  principles  exhibit  but  three 
or  four  elements,  of  which,  then,  the  whole  infinite  variety 
of  plants  is  composed  ! !  These  are  oxygen,  hydrogen, 
carbon,  and  nitrogen  (in  a  few  cases  only,  phosphorus, 
sulphur,  iodine,  and  bromine) ;  and  from  the  different 
proportions  in  which  these  few  substances  unite  and  com- 
bine with  each  other,  result  the  infinite  variety  of  taste, 
smell,  color,  &c,  in  the  products  of  the  vegetable  king- 
dom. 

§  305.  All  vegetable  matters  may,  with  regard  to  their 
composition,  be  divided  into  four  great  classes  : 

1.  Into  unsaleable  vegetable  substances;  that  is,  such 
as  do   not  combine  with    the   acids   to  form   salts   (see 
Chap.  IV). 

2.  Into  salijiable  bases ;  that  is,  substances  which,  like 
the  oxides  of  metals,  form  salts  in  combination  with  the 
acids. 

3.  Vegetable  acids.     These  affect  vegetable  colors  like 
the  mineral  acids  (see  Introduction,  38)  ;    change  blue 
litmus  paper  into  red,  and  with  the  mineral  oxides  or  vege- 
table bases  form  salts. 

4.  Substances  nf  an  undetermined  nature,  which  are  not 
comprised  by  either  of  the  three  preceding  classes. 

I.     UNSALIFIABLE  VEGETABLE  SUBSTANCES. 

§  306.  The  unsalifiable  vegetable  substances  may 
again  be  divided  into  neutral  and  watery.  Neutral  are 


304  WOODY    FIBRE.  — STARCH. 

those  in  which  the  hydrogen  is  to  the  oxygen  as  in  wa- 
ter;  that  is,  in  the  proportion  of  one  to  eight  (see  Chap. 
1,  §  25).  Watery,  on  the  contrary,  are  those  which 
possess  a  greater  quantity  of  hydrogen  than,  in  combina- 
tion with  the  oxygen  they  contain,  is  necessary  to  form 
water.  Their  hydrogen,  therefore,  is  to  their  oxygen  in  a 
larger  proportion  than  one  to  eight. 

A.    NEUTRAL  UNSALIFIABLE  VEGETABLE  SUBSTANCES. 

§  307.  The  most  remarkable  neutral  unsalifiable  sub- 
stances in  the  vegetable  kingdom  are  the  woody  Jibre, 
starch,  gum  or  mucilage,  and  sugar.  When  perfectly  pure 
they  are  all  white,  inodorous,  and,  with  the  exception  of 
sugar,  tasteless.  They  are  all  solid,  insoluble  in  pure  al- 
cohol, and  burn  with  an  acid  smoke,  which  reddens  litmus 
paper. 

1.      Woody  Fibre. 

§  308.  This  principal  ingredient  of  all  plants,  but  more 
especially  of  trees,  is  obtained  by  removing  all  soluble 
parts  from  wood  ;  which  is  done  by  boiling  it  for  a  consid- 
erable time  in  water,  and  then  exposing  it  with  alcohol  to 
a  gentle  heat. 

Properties.  It  is  white,  inodorous,  tasteless,  and  spe- 
cifically lighter  than  water.  It  is  insoluble  in  water,  al- 
cohol, or  any  diluted  acid.  Hence  the  fitness  of  hemp, 
flax,  and  cotton  to  be  bleached  with  water  and  chlorine. 
Concentrated  nitric,  sulphuric,  or  muriatic  acid  destroys 
it  or  gives  it  a  yellowish  brown  color.  Concentrated  sul- 
phuric acid  blackens  it,  and  with  the  assistance  of  heat 
converts  it  into  charcoal.  When  burnt  in  close  vessels 
(dry  distillation)  it  affords  tar  and  vinegar  or  acetic  acid. 

2.     Starch. 

§  309.  Starch  is  obtained  principally  from  all  kinds  of 
grain  ;  but  also  from  roots  and  a  variety  of  other  vegeta- 


GUM    OR    MUCILAGE.  — SUGAR.  305 

ble  substances  (particularly  from  potatoes),  by  grinding 
them  to  powder,  and  washing  them  frequently  with  cold 
water.  When  dissolved  in  hot  water  it  forms  a  kind  of 
glue  or  paste,  used  by  bookbinders.  It  is  soluble  also  in 
the  acids,  and  when  boiled  in  a  solution  of  sulphuric  acid, 
a  sort  of  sugar  (sugar  of  starch)  is  obtained.*  Heated  in 
close  vessels  it  yields  a  sort  of  vinegar,  similar  to,  though 
not  exactly  the  same  as  that  obtained  from  the  dry  distilla- 
tion of  woody  fibre  (§  308). 

3.      Gum  or  Mucilage. 

§  310.  Mucilage  or  gum  occurs  in  different  plants 
and  their  organs,  and  is  used  for  technical  and  phar- 
maceutical purposes.  When  the  substance  is  fluid,  it  is 
termed  mucilage  ;  when  it  occurs  in  a  solid  state  it  is  called 
gum. 

Properties.  Both  are  easily  soluble  in  water,  in  solu- 
tions of  pure  alkalies,  and  in  diluted  acids.  Gum,  howev- 
er, is  much  harder  and  more  brittle  than  mucilage.  By 
strong  sulphuric  acid  it  may  be  decomposed  into  water, 
acid  and  charcoal.  By  the  action  of  nitric  acid  it  is  con- 
verted into  Mucous  acid,  an  acid  peculiar  to  mucilaginous 
substances,  (which  has  not,  as  yet,  been  obtained  from  any 
other  body  in  nature),  hence  the  name.  When  distilled 
in  a  retort  it  yields,  likewise,  a  sort  of  vinegar  (acetous 
acid). 

4.     Sugar. 

§  311.  This  substance,  which  is  known  by  its  sweet 
taste,  solubility  in  water,  and  capacity  of  yielding  (when 
properly  treated)  spirituous  liquors,  may  be  obtained  from 
several  plants,  from  fruit,  carrots,  raisins,  liquorice,  manna, 
honey,  &/c  ;  but  more  especially  from  the  sugar-cane.  The 
pithy  substance  of  this  well  known  plant  of  southern  climes 
contains  a  sweet  juice,  which,  with  a  small  additionx  of 
slaked  lime,  is  evaporated  in  copper  vessels  until  it  be- 

*  The  same  sugar  is  obtained  spontaneously  in  the  germination  of 
grains. 

26* 


306  ESSENTIAL    OILS. 

comes  thick  and  tenacious.  This  mass,  upon  cooling, 
shoots  into  white  crystals,  which  are  afterwards  separated 
from  the  liquid.  The  crystals  occur  in  commerce  as  raw 
sugar  ;  the  remaining  liquid  is  filled  in  hogsheads  and 
sold  as  molasses.  The  raw  sugar  is  afterwards  again  dis- 
solved in  lime-water  and  refined  by  bullocks'  blood,  which, 
in  the  process  of  boiling,  floats  on  top  and  draws  all  impu- 
rities with  it.  The  liquid  is  then  cast  into  moulds,  and 
upon  cooling,  forms  the  loaf-sugar  of  commerce.  Sugar 
obtained  in  this  manner  is  easily  soluble  in  cold,  but 
much  better  in  warm  water  ;  from  a  solution  of  which  it 
crystalizes  in  prisms,  which  are  called  candied  sugar. 
Distilled  with  nitric  acid,  it  becomes  converted  into  oxalic 
acid(  which  will  be  described  hereafter)  ;  but  when  strong- 
ly heated  with  it,  into  acetic  acid  and  charcoal.  Its  ap- 
plication in  domestic  economy  and  medicine  is  sufficiently 
known. 

B.     WATERY  UNSALIFIABLE  VEGETABLE  SUBSTANCES. 

§  312.  These  occur  either  already  formed  by  nature, 
or  are  prepared  by  a  process  of  art.  To  the  former  belong 
the  volatile  or  essential  oils,  the  fat  oils,  wax,  resin,  &,c ; 
to  the  latter,  alcohol  and  the  various  kinds  of  ether.  All 
these  substances  are  more  or  less  fusible  and  soluble  in 
pure  alcohol.  On  account  of  the  great  quantity  of  hydro- 
gen which  they  contain,  they  are  highly  combustible,  and 
nerve,  on  this  account,  for  fuel  and  light. 

1.      Volatile  or  Essential  Oils. 

§  313.  These  oils  are  distinguished  by  a  strong,  pen- 
etrating smell,  and  an  acrid  taste.  They  are  obtained  from 
the  greatest  variety  of  vegetable  organs,  viz  :  from  flowers, 
fruits,  wood,  leaves,  roots,  &/c,  and  differ  much  from  each 
other  in  color,  taste,  smell,  fluidity,  and  combustibility  (as, 
for  instance,  the  oils  of  camomile,  of  cloves,  of  peppermint, 
of  wax,  of  cinnamon,  &c)  ;  most  of  them,  however,  pos- 
sess the  following  properties  :  They  have  generally  a  yel- 
low color  and  a  sharp  taste ;  they  boil  more  easily  than 


FAT    OILS.  307 

water,  are  readily  soluble  in  alcohol,  (less  so  in  water), 
burn  spontaneously  when  mixed  with  nitric  acid  ;  and  yield, 
as  the  product  of  their  combustion,  a  resinous  substance, 
or  an  acid.  They  thicken,  when  exposed  for  a  long  time 
to  the  atmosphere,  on  account  of  the  oxygen  which  they 
absorb.  By  dry  distillation  in  close  vessels  they  are  de- 
composed, and  yield  principally  carbureted  hydrogen  and 
charcoal  (see  §  84  and  §  73).  They  are  used  for  the 
preparation  of  odoriferous  waters,  for  spice,  essences, 
drinks,  &/c. 

Camphor,  which,  although  in  a  solid  state,  belongs  like- 
wise to  the  essential  oils,  is  not  inflamed  by  nitric  acid, 
but  is  converted  into  a  distinct  acid,  which  is  called  Cam- 
phoric acid.  It  is  capable  of  crystalization  ;  burns  with 
an  aromatic  smoke,  and  in  combination  with  the  alkalies 
and  oxides,  forms  a  class  of  salts,  which  have  received  the 
appellation  of  Camphorates. 

2.     Fat  or  Fixed  Oils. 

§  314.  These  oils,  which  are  obtained  by  mechanical 
pressure,  from  certain  vegetables,  differ  from  each  other  ac- 
cording to  the  nature  of  the  plant  from  which  they  are  pro- 
cured ;  hence  the  different  properties  of  olive-oil,  linseed- 
oil,  nut-oil,  oil  of  almonds,  &>c.  With  the  exception  of  co- 
coa-butter, they  are  all  liquid,  have  a  yellow  color,  a  faint, 
sweetish  taste,  and  when  perfectly  pure,  are  destitute  of 
smell.  They  are  all  specifically  lighter  than,  and  insoluble 
in  water.  They  are  decomposed  by  dry  distillation,  and 
combine  with  the  alkalies  to  soap.  All  of  them  are  highly 
inflammable,  and  eminently  calculated  for  combustion. 
On  account  of  the  two  last  mentioned  properties  they  are 
valuable  articles  of  domestic  economy. 

When  the  fixed  oils  are  mixed  with  lamp-black,  charcoal, 
cotton,  flax  or  wool,  enough  heat  is  given  off  to  produce,  in 
some  instances,  spontaneous  combustion.  The  greatest  pre- 
caution therefore  ought  to  be  used  in  cotton-mills,  and  in  all 
other  machineries  where  oil  comes  in  contact  with  charcoal  or 
oil. 


308  RESINS. 

3.     Resins. 

§  315.  The  name  of  resins  has  been  applied  to  the 
thickened  juices  of  trees,  which  exude  from  the  incisions 
or  apertures  made  in  their  bark.  To  this  class  of  bodies 
belong  the  gum-resins,*  aaafcctida,  gum-ammoniac,  aloes, 
gamboge,  myrrh,  copal,  dragon's  blood,  sandarach,  turpen- 
tine, common  resin,  caoutchouc  or  India  rubber,  amber,  and 
a  variety  of  other  substances. 

Most  resins  have  a  yellow  color,  and  are,  in  a  pure  state, 
perfectly  inodorous.  Their  taste  is  bitter  ;  they  are  easily 
fusible;  but  not  soluble  in  water,  although  readily  dissolved 
in  spirits  of  wine,  naphta,  the  fixed  oils  and  the  alkalies. 
They  burn  with  a  dense  smoke,  emitting  a  very  disagree- 
able odor,  and  possess  the  remarkable  property  of  becom- 
ing electric  by  friction.  (These  phenomena  have  been 
treated  of  in  Natural  Philosophy,  Chapter  VIII).  The 
gum-resins  are  extensively  used  in  medicine.  Common 
resin  is  employed  for  physical  and  technical  purposes,  viz  : 
for  varnishes,  electrical  machines,  salves,  balsams,  &c. 

India  rubber  or  gum  clastic  is  obtained  principally  from 
two  trees  (the  Hoevea  Caoutchouc  and  Satropha  Elastica) 
which  grow  in  Brazil.  When  an  incision  is  made  in  the 
bark  of  these  trees,  a  milky  juice  exudes,  which,  in  contact 
with  the  atmosphere,  becomes  soon  changed  into  a  solid, 
elastic  substance,  in  which  state  it  occurs  in  commerce. 
It  is  supposed  to  contain  a  considerable  quantity  of  nitro- 
gen, burns  with  a  bright  flame,  is  insoluble  in  water,  but 
dissolves  in  ether  and  the  volatile  oils.  It  possesses  the 
invaluable  property  of  rendering  cloth,  leather,  and  other 
substances  used  as  wearing  apparel,  impervious  to  water. 
It  is  on  this  account  used  for  over-shoes,  for  water-proof 
boots,  and  such  similar  purposes.  It  absorbs  also  the 
marks  made  with  lead-pencil  upon  paper,  and  is  on  this  ac- 
count an  indispensable  article  to  the  artist  and  draftsman. 

REMARK.  But  few  of  the  resinous  substances  have  as  yet 
been  thoroughly  examined  ;  their  ingredients  and  the  propor- 
tion in  which  they  are  combined  are,  therefore,  far  from  being 
satisfactorily  known. 

*  So  called  from  their  apparent  similarity  to  gum. 


WAX.— ALCOHOL.  309 

4.     Wax. 

§  316.  This  substance  is  obtained  from  vegetable 
matter  (berries,  leaves,  &c),  as  well  as  from  bees.  It 
differs  from  resin  by  its  greater  fusibility,  ductibility,  and 
peculiar  smell.  It  is  not  so  easily  soluble  in  ether,  or  al- 
cohol, as  resin.  It  melts  at  about  150°  Fahrenheit,  and 
forms  a  transparent  fluid,  which,  as  it  cools,  gradually  ac- 
quires consistency,  and  finally  returns  to  the  solid  state. 
Upon  decomposition  it  is  found  to  contain  82  per  cent  of 
carbon,  and  13  per  cent  of  hydrogen  ;  consequently,  95 
per  cent  of  combustible  elements.  This  circumstance 
accounts  sufficiently  for  the  pure,  bright  flame  of  wax  can- 
dles, preferred,  sometimes,  even  to  those  of  the  fixed  oils. 

5.     Alcohol. 

§  317.  This  substance,  the  product  of  fermentation 
of  all  sugary  parts  of  plants,  is  contained  in  a  greater  or 
less  quantity  in  all  spirituous  liquors,  and  produces  their 
well-known  intoxicating  effects.  It  is  considerably  lighter 
than  water,  and  its  specific  gravity  affords  a  proof  of  its 
rectification,  and  the  rectification  of  other  spirits.  (The 
lighter  they  are  the  less  water  is  contained  in  them  ;  the 
greater,  therefore,  is  the  quantity  of  water  they  contain).* 

Alcohol,  when  pure,  is  perfectly  colorless,  has  a  pe- 
culiar strong,  penetrating  smell,  a  burning  taste,  and  is 
easily  volatilized.  It  boils  at  a  much  lower  temperature 
than  water  (at  176°  Fahrenheit),  but  has  not,  as  yet,  been 
made  to  congeal  by  any  known  method  of  producing  arti- 
ficial cold.  Even  mixed  with  water  it  requires  several  de- 
grees below  zero  (over  35°  below  the  freezing  point  of 
water)  to  freeze  it.  It  unites  chemically  with  water,  evolv- 
ing considerable  heat  during  the  combination.  It  is  high- 
ly inflammable,  absorbs  most  of  the  gases,  and  dissolves 
many  of  the  vegetable  acids,  volatile  oils,  resins  and  bal- 

*  Upon  this  principle  are  founded  the  wine,  beer  and  brandy 
scales  (see  chemical  apparatus,  Fig;.  LVI  and  LVII,  pages  33  —  35) 
which  exhibit  the  strength  of  these  liquors  by  the  depth  to  which 
they  immerse  in  them.  Hence  the  appellation  of  1st,  2d,  3d,  4th, 
and  5th  proof. 


310  ETHER    AND    NAPHTA. 

sams.  It  acts  also  on  iodine,  sulphur,  phosphorus,  some 
of  the  alkalies,  and  some  of  the  salts  (chloride  of  lime,  sul- 
phate of  iron,  and  some  of  the  nitrates).  //  preserves  veg- 
etable and  animal  substances  from  putrefaction ;  but  is 
itself  decomposed,  when  passed  through  a  red  hot  copper 
tube,  into  a  fine,  light  soot,  resembling  lamp-black,  and  a 
great  quantity  of  carbureted  hydrogen,  (one  ounce  of  al- 
cohol yielding  several  cubic  feet  of  carbureted  hydrogen). 

Uses  of  JllcohoL  Alcohol  is  used  in  a  great  number  of 
preparations  for  domestic,  technical,  and  medicinal  purposes ; 
and  yet  this  highly  important  substance  is  composed  of  the 
same  elements,  as  all  vegetable  matters  we  have  thus  far  de- 
scribed ;  which  proves  how  much  depends  upon  the  proportion 
in  which  simple  bodies  combine.  Thus,  while  woody  fibre  con- 
sists of  4  equivalents  of  carbon  and  4  of  water  ;  starch  of  4 
equivalents  of  carbon  and  6  of  water,  and  sugar  of  4  equiva- 
lents of  carbon  and  8  of  water,  alcohol  consists  of  4  equivalents 
of  carbon  and  12  of  water.  The  ratio,  therefore,  in  which 
carbon  unites  with  water  in  these  four  substances  is  as  1  to  J, 
1  to  1^-,  1  to  2,  and  1  to  4  ;  and  in  these  different  proportions 
alone  lies  the  reason  of  the  immense  difference  in  the  proper- 
ties of  woody  fibre,  starch,  sugar,  and  alcohol ! ! 

The  process  of  Fermentation  will  be  described  hereafter 
(Chap.  VII),  under  the  head  of  spontaneous  decomposition  of 
organic  substances. 

6.     Ether  and  Naphta. 

§  318.  When  alcohol  is  distilled  with  the  different  acids, 
it  becomes  converted  into  Ether,  a  liquid  which  is  lighter 
than  alcohol,  mixes  in  all  proportions  with  the  volatile  oils, 
and  dissolves  wax,  resin,  vegetable  extracts  and  acids,  and 
some  of  the  alkalies.  After  distillation  a  yellowish  liquid 
remains,  which,  when  purified  with  a  solution  of  potash, 
will  float  on  top,  and  is  called  oil  of  wine.  This  combines 
again  with  the  acids,  and  forms  a  class  of  substances 
known  by  the  name  of  Naphtas.  Both  products,  the  ethers 
and  naphtas,  are  strongly  odoriferous,  extremely  volatile, 
similar  to  the  volatile  oils,  but  more  easily  converted  into 
vapor,  more  inflammable,  and  specifically  lighter  than  al- 
cohol. The  different  kinds  of  ether  are  distinguished 
from  each  other  by  prefixing  the  name  of  the  acid  from 


SALIFIABLE    VEGETABLE    BASES.  311 

which  they  are  derived.  Thus,  the  ether  prepared  from 
alcohol  and  sulphuric  acid  is  called  sulphuric  ether  ;  that 
which  is  obtained  frdm  muriatic  acid  and  alcohol,  is  called 
muriatic  ether,  and  so  of  the  rest.  A  similar  nomencla- 
ture has  been  adopted  for  the  naphtas. 

Sulphuric  ether  is  by  far  the  most  important  substance 
of  them  all,  and  extensively  used  in  medicine.  It  is  ob- 
tained by  distilling  together  equal  volumes  of  alcohol  and 
sulphuric  acid. 

II.     SALIFIABLE  VEGETABLE  BASES. 

§  319.  This  class  of  vegetable  substances,  the  result 
of  the  discoveries  of  modern  chemists,  contains  about  30 
different  bodies,  extracted  mostly  from  narcotic  and  me- 
dicinal plants,  by  the  action  of  magnesia.*  They  are 
generally  white,  have  a  sharp,  bitter  taste,  may  be  obtain- 
ed in  crystals  or  as  a  powder,  and  change,  when  burnt  or 
in  a  state  of  moisture,  red  vegetable  colors  into  blue. 
They  are  not  easily  soluble  in  water,  better  in  ether,  but 
most  readily  in  alcohol.  With  the  acids,  (particularly  the 
sulphuric,  nitric,  and  muriatic  acids)  they  form  salts  which 
are  soluble  in  water,  and  easily  decomposed  by  potash. 
Their  ultimate  principles  are  oxygen,  hydrogen,  carbon, 
and  nitrogen  ;  the  latter  element  only  in  a  proportion  of 
from  4  to  8  per  cent.  Many  of  them  are  poisonous  or 
affect  the  animal  body. 

The  salts  which  these  bases  form  in  combination  with 
the  acids,  are  denominated  after  the  acids  according  to 
the  rules  laid  down  in  Chapter  IV,  §  232. 

*  The  names  are,  Nicotine,  Chinine,  Cinchonine,  Gentianine, 
Daphnine,  Corydaline,  Zanthopicrite,  Hesperidine,  Guaranine, 
pure  bitter  extract,  Morphium,  Opium  (Narcotine),  Picrotoxine, 
Strychnine,  Brucine,  Solanine,  Coffeeine, Narcotic  extract,  Delphi- 
nine,  Veratrine  (Sabadi(line),  Emetine,  Piperin,  Plumbagin,  Ja- 
maicin,  Surinamin,  jlsparagin,  Olivil,  and  several  other  organic 
bases,  whose  existence,  however,  is  not  yet  sufficiently  proved. 


312  TARTARIC   ACID. 

'.'•*•  -    .  t 

III.     VEGETABLE  ACIDS. 

[In  these  substances  the  hydrogen  is  to  the  oxygen  in  a  less 
proportion  than  is  necessary  to  form  water  ;  that  is,  in  a  less 
proportion  than  1  to  8.  (Compare  §  25,  page  75).] 

§  320.  Characteristics  of  vegetable  acids.  The  vege- 
table acids  are  easily  distinguished  from  the  neutral  or 
salifiable  vegetable  substances,  by  their  sour  taste,  by 
changing  the  blue  colors  of  vegetables  into  red,  and  by 
their  combination  with  the  oxides  of  the  mineral  and  vege- 
table kingdoms.  They  are  either  capable  of  crystalization 
(fixed),  of  distillation  (liquid),  or  of  sublimation  (volatile). 
They  occur  either  already  formed,  in  particular  organs  of 
plants,  or  as  salts,  combined  with  inorganic  or  organic 
bases,  and  are  of  great  application  in  domestic  economy, 
in  medicine  and  in  the  arts. 

A.     FIXED  VEGETABLE  ACIDS. 

§  321 .  The  vegetable  acids  belonging  to  this  class 
are  generally  white,  and  easily  soluble  in  water.  The  most 
remarkable  among  them  are  Tartaric  acid,  Citric  acid, 
Malic  acid,  Gallic  acidy  Vegetable  jelly  and  humous  acid, 
(in  several  roots,  berries  and  in  potatoes). 

1.      Tartaric  Acid. 

§  3*22.  This  acid  occurs,  in  its  simple  form,  in  tama- 
rinds, in  grapes,  pine-apples  and  pepper.  It  may  also  be 
obtained  from  the  well-known  salt,  cream  of  tartar  (tar- 
tarate  of  potash)  by  boiling  it  with  an  admixture  of  chalk, 
white  marble  or  oyster-shells.  The  tartarate  of  lime 
thence  obtained  as  a  precipitate  is  gently  heated  with  oil 
of  vitriol,  the  liquid  afterwards  evaporated  to  thickness,  and 
decanted  from  the  sulphate  of  lime  (gypsum)  which  falls 
to  the  bottom.  This  liquid,  upon  further  evaporation,  or 
upon  cooling,  forms  regular,  prismatic  crystals,  of  a  strong 
acid  taste,  which  are  easily  soluble  in  water,  and  fusible. 
They  unite  with  the  different  alkaline  and  earthy  bases, 


CITRIC    ACID. -MALIC    ACID.  313 

and  form  a  class  of  salts  known  by  the  name  of  tartrates. 
The  most  remarkable  among  them  is  the  tartrate  of  pot- 
ash or  vegetable  salt,  which  is  formed  by  neutralizing  tar- 
tar with  carbonate  of  potash  ;  and  the 

Bi-tartrate  of  potash  or  tartar  is  a  solid  substance,  spon- 
taneously deposited  by  all  kinds  of  wine,  which  by  being 
dissolved,  filtered,  and  treated  with  clay,  yields  the  cream 
of  tartar,  from  which  tartaric  acid  is  prepared. 

2.     Citric  Acid. 

§  323.  This  occurs  in  its  simple  form,  or  mixed  with 
malic  acid  (see  the  following  section)  in  a  variety  of  fruits. 
It  may  also  be  procured  by  the  action  of  nitric  acid  or 
chlorine  on  many  organic  compounds.  The  way  in  which 
it  is  commonly  obtained  is  by  saturating  boiling  lemon  or 
lime  juice  with  carbonate  of  lime  (see  Chap.  IV,  §  280). 
To  the  citrate  of  lime  thus  obtained,  boiling  water  and  oil 
of  vitriol  is  added,  and  the  liquid  afterwards  filtered  and 
evaporated  until  the  acid  is  obtained  in  form  of  crystals. 
Citric  acid  becomes  spontaneously  decomposed  and  cover- 
ed with  a  scum,  even  in  closed  vessels,  and  slowly  heated 
with  alcohol  it  becomes  converted  into  vinegar.*  The 
salts  formed  by  the  combination  of  citric  acid  with  the 
different  salifiable  bases  are  called  citrates. 

3.     Malic  Acid. 

§  324.  This  acid  is  next  to  acetic  acid,  and  oxalic  acid 
(see  §  334  and  §  325)  most  generally  distributed  in  the 
vegetable  kingdom,  and  occurs  in  the  roots,  stalks,  blos- 
soms, and  fruits  of  a  great  many  plants.  It  is  generally 
extracted  from  the  berries  of  the  sorb  or  service  tree.  It 
is  liquid,  soluble  in  water,  but  crystalizes  only  with  great 
difficulty.  It  undergoes  spontaneous  decomposition,  and 
is  by  nitric  acid  converted  into  oxalic  acid.  The  salts  of 
this  acid  are  called  malates. 

*  Gmehlen's  Chemistry,  Heidelberg,  1830. 

27 


314          OXALIC,   GALLIC,    AND    PECTIC   ACIDS. 

4.  Oxalic  Acid. 

§  325.  The  mode  of  obtaining  oxalic  acid  has  already 
been  described  in  §  324.  It  has  a  strong,  sour  taste, 
changes  blue  vegetable  colors  into  red,  and  forms,  upon 
evaporation,  regular  crystals,  which  by  a  red  heat  are 
again  decomposed,  and  leave  nothing  but  charcoal.  They 
are  soluble  in  water  and  boiling  alcohol.  With  the  dif- 
ferent mineral  bases  they  form  a  class  of  salts,  which  are 
distinguished  by  the  name  of  oxalates.  The  principal 
ones  are  oxalate  of  potash,  soda,  lime,  strontia,  ammonia, 
baryta,  and  magnesia. 

5.  Gallic  Acid. 

§  326.  Gallic  acid  is  contained  in  all  astringent  veg- 
etable substances,  particularly  in  the  bark  of  trees;  and  is 
chiefly  obtained  by  dissolving  powdered  gall-nut  in  water, 
at  a  gentle  heat ;  when  the  liquid  is  filtered  and  exposed 
to  the  atmosphere  it  is  covered  with  a  thin  scum,  which 
from  time  to  time  must  be  removed.  When  evaporated 
to  about  half  its  volume  it  is  decanted.  The  sediment  is 
then  again  digested  with  water  and  the  same  process  is 
repeated  several  times.  The  residue  is  afterwards  dis- 
solved in  hot  water,  from  which,  upon  cooling  and  filtering, 
the  acid  shoots  in  regular  crystals. 

Gallic  acid  has  a  sharp,  sweetish  (not  sour)  taste.  When 
sublimed  it  reddens  litmus  paper ;  melts,  at  a  gentle  heat, 
to  a  colorless  oil,  and  evaporates,  when  heated,  with  white 
fumes  and  a  faint  smell,  leaving  nothing  but  a  little  char- 
coal. When  saturated  with  carbonate  of  potash  or  muri- 
ate of  tin  a  yellowish  precipitate  is  formed,  which  is  known 
by  the  name  of  tan,  and  is  used  in  the  preparation  of 
leather.  Gallic  acid  is  a  principal  ingredient  of  writing 
ink. 

6.      Vegetable  Jelly,  or  Pectic  acid. 

§  327.  This  acid  is  obtained  from  the  tremulous,  soft 
substance  deposited  by  the  juice  of  certain  fruits.  It  may 
be  purified  by  decanting  the  juice  and  washing  it  with  a 


BITUMOUS    ACID.-BENZOIC    ACID.  315 

little  cold  water.  It  appears,  when  dry,  in  transparent 
leaves,  which  do  not  adhere  to  the  sides  of  the  vessel  — 
has,  when  moist,  a  decidedly  sour  taste,  and  reddens  litmus 
paper.  It  combines  readily  with  the  alkalies  and  other 
salifiable  bases. 

7.     Bitumuus  Acid* 

§  328.  Bitumous  acid  is  produced  from  turf,  mineral 
pitch,  bituminous  wood,  mold  and  such  similar  substan- 
ces, by  dissolving  them  in  liquid  potash  and  precipitating 
the  solution  by  the  addition  of  some  other  acid.  The  acid 
thus  obtained  appears  in  brown  flakes,  but  when  perfectly 
dry  it  is  a  brown,  brittle  mass,  of  great  lustre.  By  dry 
distillation  it  becomes  decomposed  into  carbonic  acid,  car- 
bureted hydrogen  gas,  water,  oil,  and  acetic  acid. 

The  same  acid  is  also  produced  spontaneously  during  the 
putrefaction  of  a  great  many  vegetable  substances,  particularly 
of  that  of  the  woody  fibre.  (See  Chap.  VII,  spontaneous  de- 
composition of  vegetable  substances). 

B.     VEGETABLE  ACIDS,  CAPABLE  OF  SUBLIMATION. 

§  329.  The  most  important  acids  belonging  to  this 
class  are  the  benzoic,  succinic,  and  boletic  adds,  which  are 
found,  already  formed,  in  many  plants,  but  may  be  obtain- 
ed also  by  the  combustion  of  a  number  of  vegetable  sub- 
stances. 

1.     Benzole  Acid. 

^  330.  Benzoic  acid  occurs  in  dragons'  bloody  Peru- 
vian balsam,  and  a  gum  (found  at  Botany  Bay)  called 
Benzoin  (hence  its  name)  ;  also  in  a  variety  of  volatile 
and  essential  oils;  in  cloves,  and  in  some  of  the  liquids  of 
quadrupeds.  It  is  now  generally  obtained  by  heating 
benzoin  with  dilute  sulphuric  acid,  or  by  melting  it  at  a 
gentle  heat.  It  crystalizes  in  white,  soft  needles  of  the 
appearance  of  mother  of  pearl,  reddens  blue  vegetable  col- 
ors, melts  at  a  gentle  heat,  like  fat,  and  evaporates  at  its 
melting  point  in  form  of  a  white  smoke.  It  combines 


316      SUCCINIC,    BOLETIC,  AND    ACETIC  ACID. 

with  the  mineral  alkalies  and  oxides,  and  forms  a  kind  of 
salts  called  benzoates. 

2.     Succinic  Acid. 

§  331.  This  acid  occurs,  already  formed,  in  amber, 
and  is  obtained  from  it  by  slow  distillation.  It  is  also  pro- 
cured by  boiling  powdered  amber  in  water.  It  forms  white, 
transparent  crystals,  melts  at  a  gentle  heat,  and  becomes 
converted  into  white,  sharp  vapors,  which  condense  into 
flakes,  and  finally  into  long,  crystaline  needles.  It  com- 
bines with  the  mineral  and  volatile  alkalies  (ammonia). 
The  salts  which  it  forms  are  called  succinates. 

3.     Boletic  Acid. 

§  33*2.  This  acid  is  obtained  from  the  juice  of  a  par- 
ticular plant,  called  Boletus  Pscudoignarius.  It  crys- 
talizes  in  four-sided  prisms.  Its  taste  is  similar  to  tartaric 
acid.  In  fire  it  becomes  converted  into  white,  suffocating 
vapors. 

C.     LLQUID  VEGETABLE  ACIDS  (CAPABLE  OF  DISTILLA- 
TION). 

§  333.  To  this  class  belong  acetic  acid,  from  which 
vinegar  is  obtained,  Prussic  acid,  and  cyanic  acid.  The 
two  last  have  already  been  described  in  mineral  chemistry 
(§  89,  —  <j  92) ;  because  they  can  be  produced  by  art  from 
the  chemical  combination  of  their  elements.  But  they 
occur  also  in  vegetables,  and  seem,  indeed,  to  be  an  in- 
termediate link  between  mineral  and  vegetable  formation. 

It  will  appear  from  reviewing  §  89  —  §  92  that  Prussic  and 
cyanic  acids  are  ternary  combinations  of  carbon,  nitrogen  and 
oxygen,  and  on  this  account  already  exceptions  to  other  inor- 
ganic formations,  which  are  generally  products  of  two  and 
two  elements.  (Compare  the  remark,  page  25'3). 

1.     Acetic  Acid  (Vinegar). 
§  334.     This  acid  occurs  either  in  its  simple  form,  or 


ACETIC    ACID. 


317 


mixed  with  potash  and  lime  in  the  juice  of  a  great  many 
plants,  particularly  in  the  sap  of  trees,  and  in  some  min- 
eral waters.  It  is  also  formed  at  the  spontaneous  de- 
composition of  vegetable  substances,  especially  such  as 
contain  more  or  less  alcohol  —  in  grapes,  fruits,  &.c,  (see 
Chap.  VII,  acetous  fermentation)  —  and  at  the  dry  distil- 
lation or  imperfect  combustion  of  plants.  It  is  the  princi- 
pal ingredient  of  common  vinegar,  which  consists  chiefly 
of  acetic  acid,  mucilage,  coloring  matter  and  water. 

Acetic  acid  is  commonly  prepared  by  mixing  wine,  cider,  beer, 
or  dilute  spirit  of  wine  with  vinegar,  and  exposing  the  mixture 
in  an  open  vessel  (for  several  weeks)  to  a  heat  of  about  from 
80  to  90°  Fahrenheit.  If  vinegar  be  distilled  to  thickness,  the 
residue  is  almost  pure  acetic  acid,  mixed  with  a  small  quantity 
of  water.  If  distilled  vinegar  be  exposed  to  severe  cold,  part 
of  its  water  freezes,  and  the  remaining  vinegar  is  much  strong- 
er than  before. 

Properties  of  acetic  acid.  Acetic  acid  in  a  pure  state, 
as  radical  vinegar,  is  colorless,  possesses  a  well-known, 
strong  smell,  a.  very  acid  taste,  and  is  capable  of  being  en- 
tirely volatilized.  It  boils  a  little  above  212°,  and  freezes 
at  about  27°  below  the  freezing  point  of  water.  It  acts 
speedily  on  all  oxidable  metals,  such  as  iron,  lead,  tin, 
copper,  &c,  and  combines  with  them,  as  well  as  with  oth- 
er mineral  oxides,  and  forms  with  them  a  distinct  class  of 
salts  —  the  acetates.  The  most  remarkable  among  these 
are  the  acetates  of  potash  (arcanum  tartari),  of  soda,  ba- 
ryta, magnesia,  copper,  and  lead.  The  acetate  of  lead  is 
produced  in  great  abundance  at  the  manufacture  of  sugar 
of  lead.  Most  of  the  other  acetates  are  used  in  medicine, 
and  for  technical  purposes. 

Acetic  acid  combines  also  with  sugar,  gum,  the  essen 
tial  oils,  alcohol  and  other  organic  substances.  When,  in 
form  of  vapors,  it  is  passed  through  a  red-hot  iron  tube,  it 
is  decomposed  into  carbonic  acid  and  carbureted  hydro- 
gen gas,  which  proves  that  acetic  acid  differs  in  its  com- 
position from  alcohol,  only  in  the  greater  proportion  of  its 
oxygen. 

27* 


318  PRUSSIC    AND    CYANIC  ACIDS. 

2.  Prussic  Acid. 

§  335.  This  volatile  and  most  poisonous  acid  is  found 
in  several  plants,  particularly  in  almonds,  in  the  stones  of 
peaches,  plumbs,  cherries,  &c,  also  in  the  leaves  and  bark 
of  trees,  &,c  ;  but  is  generally  obtained  by  the  combus- 
tion with  potash  of  several  animal  substances ;  for  instance, 
the  blood,  which  contains  its  elements,  carbon,  nitrogen, 
and  oxygen.  When  Prussic  acid  is  treated  with  blood, 
alum,  and  vitriol  of  iron,  it  yields  the  celebrated  Berlin 
or  Prussian  blue,  which  is  an  extensive  article  of  com- 
merce. The  other  properties  of  Prussic  acid  have  already 
been  described  in  Chapter  II,  §  91  and  92.  The  same 
holds  of 

3.  Cyanic  Acid, 

which  has  been  spoken  of  in  Chap.  II,  §  89. 

REMARK.  Besides  the  vegetable  acids  here  described,  there 
are  yet  a  number  of  others,  which  have  not,  however,  been 
sufficiently  examined,  and  are  not  yet  extensively  used  in  the 
arts  ;  on  this  account  it  may  perhaps  be  well  to  omit  them  in 
an  elementary  treatise. 

IV.     VEGETABLE    SUBSTANCES    OF   AN    UNDETERMINED 

NATURE. 

§  336.  The  vegetable  substances  belonging  to  this 
class  and  their  chemical  composition  are  far  from  being 
satisfactorily  known.  But  few  of  them  have  been  obtain- 
ed in  their  simple  forms,  and  there  is  hardly  one  among 
them,  the  proportion  of  whose  elements  is  accurately  de- 
termined. They  are  nevertheless  of  great  importance  to 
the  arts,  with  regard  to  which  they  may  be  divided  into 
three  classes  :  coloring  matters,  vegetable  extracts  andfer- 
mentous  principles. 

1.     Coloring  Matters. 

§  337.  Of  these,  a  great  number  is  contained  in  the 
most  heterogeneous  plants,  and  it  may,  perhaps,  be  said 


COLORING     MATTERS.  3J9 

that  not  half  of  them  are  as  yet  sufficiently  employed  in 
the  arts.  The  following  are  the  most  remarkable  : 

1.  The  RED  color  of  alizarine,  lac-lake,  cam-wood,  saf- 
floicer  (carthamus  seed),  sanders  (red)  wood,  amatto,  and 
dragons'  blood. 

2.  The  BLUE  color  of  litmus,  indigo,  and  woad. 

3.  The    YELLOW    color   of  Fernambucco-icood,  zaffer, 
saffron,  dyer's  weed  (iceld),  fustic,  turmeric,  gamboge,  and 
rhubarb. 

4.  The  GREEN  color  of  the  black-thorn  berry,  of  the 
leaves  of  trees  ;  and 

5.  The  FALLOW  color  of  Venice-sumac  and  sanders. 
Some  of  these  dyeing  stuffs  are  soluble  in  water  or  dilute 

spirits  of  wine,  and  are  called  coloring  extracts  ;  others, 
on  the  contrary,  are  only  entirely  dissolved  in  alcohol,  like 
the  red-color  of  safflower,  of  gamboge,  &,c.  These  are 
called  resinous  colors.  They  are  all  bleached  by  chlo- 
rine and  muriatic  acid  (indigo  not  excepted).  Most  of 
them  exhibit  a  different  color  when  dissolved  with  the 
alkalies,  ammonia,  potash,  or  soda  ;  the  violet  becomes 
violet-green  ;  the  yellow  becomes  brown,  &/c.  Concen- 
trated acids  destroy  most  of  them,  as  we  have  seen  in 
treating  of  the  different  acids.  When  heated  they  burn 
with  a  sour  smoke,  and  leave,  after  combustion,  a  small 
portion  of  ashes. 

Some  of  the  salts,  when  mixed  with  different  solutions  of 
coloring  matters,  part  with  the  oxides  of  which  they  are  com- 
posed, and  leave  them  to  unite  with  the  vegetable  substances, 
the  color  of  which  is  by  this  means,  materially  changed.  The 
salts  most  liable  to  this  decomposition  are  alum,  muriate  (chlo- 
ride) of  tin,  acetate  of  lead),  and  vitriol  of  iron.  Hence  their 
use  in  dyeing. 

§  338.  Indigo  belongs  to  the  few  coloring  matters, 
which  are  obtained  from  vegetables  in  a  pure  state.  There 
are  various  kinds  of  indigo,  viz  :  red-indigo,  green-indigo, 
blue-indigo,  &c.  The  elements  of  those  which  are  belst 
known  are  oxygen,  hydrogen,  carbon  and  nitrogen.  In- 
digo is  extensively  used  in  dyeing,  on  which  account  it  is 
a  valuable  article  of  commerce. 


320       VEGETABLE  EXTRACTS — LEES 

2.      Vegetable  Extracts. 

§  339.  These  were  formerly  divided  into  sweet,  sour, 
coloring,  resinous,  glutinous,  narcotic,  and  bitter  extracts, 
most  of  them,  however,  have,  of  late,  been  found  to  belong 
to  other  classes  of  vegetable  matter  ;  wherefore  those  only 
are,  properly  speaking,  vegetable  extracts,  which  are  solu- 
ble in  water  and  dilute  spirits  of  wine,  incapable  of  crys- 
talization,  and  a  solution  of  which,  when  exposed  to  the  at- 
mosphere, precipitates  in  brown  flakes. 

The  bitter  taste  which  most  of  them  possess,  is  more 
or  less  variable ;  but  all  agree  in  the  following  properties  : 

1.  When   recently  extracted  from  the  plant  they  are 
brown,  brittle,  transparent,  and   specifically  lighter  than 
water. 

2.  They    absorb   moisture   from  the   atmosphere,  and 
leave,  when  shaken  with  water,  a  scum  at  the  surface. 

3.  They  are  soluble  in  liquid  potash  ;  but  not  in  pure 
alcohol,  ether  or  the  essential  oils. 

4.  They   become  soft  by  heat,  burn  (at  least,  some  of 
them)  and  leave  a  small  portion  of  ashes. 

None  of  them  have,  as  yet,  been  obtained  in  their 
simple  form. 

3.-     Fermentous  Principles. 

$  340.  To  this  class  of  bodies  belong  those  vegetable 
substances  which,  in  combination  with  sugary  bodies,  pro- 
duce the  spontaneous  process  of  fermentation  (see  Chap. 
VII  —  spontaneous  decomposition  of  vegetables).  They 
occur  generally  in  seeds  and  fruits,  more  seldom  in  stalks 
and  leaves  of  plants.  They  are  neither  soluble  in  water 
nor  alcohol ;  but  readily  dissolved  in  diluted  potash,  and  in 
sulphuric  or  muriatic  acid.  When  exposed  to  moisture 
they  emit  a  highly  disagreeable  smell,  similar  to  putrefying 
meat ;  proving  thereby  that  nitrogen  enters  into  their 
composition.  They  may  be  divided  into  lees  (dregs),  veg- 
etable albumen,  and  gluten. 

a.    Lees  (dregs). 
§  341.     Lees  or  dregs  are  the  sediment  deposited  by 


VEGETABLE  ALBUMEN.  — GLUTEN .      321 

all  fermentous  liquors.  They  form  a  yellowish-grey,  smeary 
mass,  which,  when  washed  with  water  has  a  peculiar  smell 
and  bitter  taste.  When  perfectly  dry,  it  forms  a  yellow- 
ish-brown, brittle  body,  which  is  but  sparingly  soluble  in 
hot  water  and  boiling  alcohol. 

b.    Vegetable  Albumen. 

§  342.  This  is  a  substance  more  or  less  contained  in 
all  vegetable  juices,  from  which  it  may  be  extracted  by 
means  of  cold  water,  in  a  manner  similar  to  starch  (see 
§  309).  It  contains  a  considerable  quantity  of  nitrogen. 
When  boiled  it  expands  in  a  sort  of  foam,  like  the  white 
of  an  egg  (hence  the  name) ;  and  when  dry  forms  a  grey, 
brittle  mass,  which  becomes  slightly  decomposed  when 
boiled  with  alcohol. 

c.    Gfat&tt. 

§  343.  This  substance  is  principally  obtained  from 
wheat  flour,  which  by  the  gradual  addition  of  water  is 
formed  into  a  soft,  ductile  paste.  This  is  afterwards 
washed  with  water,  while  the  paste  is  worked  between  the 
fingers,  until  the  water  flows  off  in  a  clear  stream.  By 
this  process  the  starch  and  vegetable  albumen  (see  last 
section)  are  carried  off,  and  the  pure  gluten  remains  in  the 
hands.  It  is  of  a  grey  color,  possessing  almost  as  much 
elasticity  as  elastic  gum,  and  may  be  drawn  out  and  will 
contract  again  like  this  substance.  It  is  insoluble  in  wa- 
ter, adheres  to  all  solid  substances,  and  appears,  when 
dry,  as  a  hard,  brittle,  greyish-brown  body.  When  moist 
it  undergoes  putrefaction,  and  emits  a  very  offensive  smell. 
When,  in  a  state  of  moisture,  it  is  boiled  in  alcohol,  it  be- 
comes decomposed  into  three  distinct  parts,  viz  :  a  yellow- 
ish, glutinous  mass  which  remains  dissolved  in  the  alcohol 
—  a  sort  of  mucilage  which  is  precipitated  —  and  a  third 
substance  which  remains  undissolved. 

The  precise  proportions  of  the  elements  of  gluten  are  not 
yet  ascertained  ;  but  whatever  its  chemical  composition 
may  be,  it  belongs  certainly  to  the  most  important  vegeta- 
ble substances,  and  affords  the  principal  nutriment  con- 
tained in  plants. 


322  RECAPITULATION 


RECAPITULATION. 

Questions  for  Reviewing  the  most  important  Principles 
contained  in  Chapter  V. 

A.     QUESTIONS  ON  THE  GENERAL  REMARKS  ON  THE  DIF- 

FERENCE   BETWEEN   ORGANIC    AND 

INORGANIC   BODIES. 

[§  297.]  Do  the  bodies  in  animated  nature  obey  the 
same  laws  to  which  they  are  subjected  in  dead  matter  ? 
As  what  may  every  living  body  be  considered  ?  Through 
what  two  periods  must  all  bodies  passt  which  are  endow- 
ed with  life  ? 

[§  298.]  In  what  consists  principally  the  difference  be- 
tween organized  and  unorganized  matter  1 

Are  the  inorganic  elements  of  plants  and  animals  also  per- 
ishable ?  What  then  is  it  that  is  destroyed  by  the  death  of  the 
animal  or  plant?  In  what  is  the  life  of  the  plant  or  animal 
seated  ?  What  must  this  directing  agent  be  superior  to  ? 

[§  299.]  What  are  we  in  inorganic  chemistry  gener- 
ally able  to  do  ?  Is  this  also  possible  with  regard  to  plants 
or  animals?  What  do  organic  bodies  even  need  for  their 
support  ? 

Give  examples. 

[§  300.]  In  what  do  the  chemical  processes  of  plants 
and  animals  take  place  ?  What  are  these  vessels  called  ? 

Do  we  know  anything  as  regards  the  manner  in  which  these 
processes  are  carried  on  ?  Do  we  know  for  certain  whether 
the  different  elements  which  we  have  discovered  in  plants  and 
animals  are  actually  chemically  combined  with  one  another, 
or  whether  they  exist  only  in  a  state  of  mixture  ? 

[§  301.]  WThere  are  the  products  of  vegetables  which 
are  used  in  domestic  economy  or  in  the  arts  seated  ?  What 
processes  are  required  for  the  collection  of  those  products 
which  are  diffused  throughout  the  whole  plant  ? 


OF    CHAPTER    V. 

[§  302.]  What  are  the  immediate  ingredients  of  plants, 
which  are  obtained  by  chemical  analysis  ? 

[§  303.]  By  what  means  may  the  liquid  and  solid 
parts  of  plants  be  again  decomposed  ?  What  are  the  ele- 
ments resulting  from  their  decomposition  ? 

Give  examples. 

[§  304.]  How  many  different  elements  result  from 
the  decomposition  of  the  more  remote  ingredients  of  plants 
into  their  ultimate  principles  ?  Which  elements  are  the 
ultimate  principles  of  plants  ? 

[§  305.]  Into  what  four  classes  may  all  vegetable  mat- 
ter be  divided  ? 

QUESTIONS  ON  THE  UNSALIFIA.BLE  VEGETABLE  SUBSTAN- 
CES. 

[§  306  ]  Into  what  two  classes  may  all  unsalifiable 
vegetable  substances  be  again  divided  ?  What  vegetable 
substances  are  called  neutral?  What  substances  are 
called  watery  ? 

[§  307.]  Which  are  the  most  remarkable  neutral  un- 
salifiable substances  from  the  vegetable  kingdom  ? 

[§  308.]  How  is  woody  fibre  obtained  ?  What  are  its 
properties  ? 

[§  309.]  How  is  starch  obtained  ?  What  are  its 
properties  ? 

[§  310.]  Where  does  mucilage  or  gum  occur  ?  When 
is  it  termed  mucilage  ?  When,  gum  1  What  are  the 
properties  of  these  substances  ?  What  are  the  peculiar 
properties  of  gum  1  Into  what  does  it  become  converted 
by  the  action  of  nitric  acid  ?  What  does  it  yield  when 
distilled  in  a  retort  1 

[§  311.]  From  what  plants  is  sugar  obtained?  By 
what  process  is  the  raw  sugar  of  commerce  obtained  from 
the  sugar-cane  ?  What  is  the  remaining  liquid  called  af- 


324  RECAPITULATION 

ter  the  sugar  shoots  in  regular  crystals  ?  By  what  means 
is  the  raw  sugar  refined,  and  made  loaf  sugar  ?  How  is 
candied  sugar  obtained  1  Into  what  does  sugar  become 
converted  when  distilled  with  nitric  acid  ? 

[^  312.]  Where  do  watery  unsalifiable  substances  oc- 
cur ?  What  watery,  unsalifiable  vegetable  substances  oc- 
cur in  nature  ?  Which  are  products  of  art  ?  What  prop- 
erty do  they  all  possess  in  a  high  degree  ? 

[§  313.]  By  what  properties  are  the  volatile  or  essential 
oils  distinguished  1  From  what  vegetable  organs  are  they 
obtained  1  What  properties  do  they  generally  possess  ? 
For  what  purposes  are  they  used  ? 

To  what  class  of  oils  does  camphor  belong  1  Into  what 
does  it  become  converted  by  nitric  acid  1  What  does  it 
form  in  combination  with  the  alkalies  and  oxides  ? 

[§  314.]  By  what  means  are  the  fats  or  fixed  oils  ob- 
tained ?  What  are  their  properties  1  What  do  they  form 
when  combined  with  the  alkalies  ?  For  what  purposes 
are  they  especially  calculated  ? 

What  may  take  place  when  the  fixed  oils  are  mixed  with 
lamp-black,  charcoal,  cotton,  flax,  or  wool  ?  What  ought  this 
to  teach  us  ? 

[§  315.]  To  what  substances  has  the  name  of  resins 
been  applied  ?  What  substances  belong  to  this  class  of 
bodies  ? 

What  is  the  color  and  property  of  most  resins?  For 
what  purposes  are  they  used  1 

How  is  India  rubber  or  gum  elastic  obtained  ?  What 
substance  is  it  supposed  to  contain  in  considerable  quanti- 
ty 1  What  invaluable  property  does  it  possess  ?  For  what 
purposes  is  it,  on  this  account,  used  ? 

[§  316.]  From  what  substances  is  wax  obtained? 
What  are  its  properties  ?  Of  what  elements  is  it  composed  ? 
How  many  per  cent  of  carbon  and  hydrogen  does  it  con- 
tain ?  What  does  this  account  for  ? 

[§  317.]  What  sort  of  product  is  alcohol  ?  Where  is 
it  contained  ? 


OF    CHAPTER    V.  325 

What  are  the  properties  of  pure  alcohol  ?  How  does  it 
act  upon  animal  and  vegetable  substances  1  By  what 
means  may  it  be  decomposed  ?  What  does  it  yield  when 
decomposed  ? 

What  is  the  difference  in  the  chemical  composition  between 
woody  fibre,  starch,  sugar,  and  alcohol  ?  What,  therefore, 
must  be  founded  in  their  different  proportions  ? 

[§  318.]  Into  what  does  alcohol  become  converted 
when  distilled  with  the  different  acids?  What  is  the  yel- 
lowish liquid  called  which  remains?  What  does  oil  of 
wine  form  when  again  combined  with  the  acids  ?  What 
properties  do  both  products  possess  ?  How  are  the  differ- 
ent kinds  of  ether  distinguished  from  one  another  ?  Give 
examples.  What  kind  of  ether  is  extensively  used  in 
medicine  ?  By  what  means  is  it  obtained  ? 

QUESTIONS  ON  THE  SALIFIABLE  VEGETABLE  BASES. 

[§  319.]  How  many  different  bodies  belong  to  this 
class?  What  are  their  properties?  What  do  they  form 
with  the  acids  ?  What  are  their  ultimate  principles  ? 
How  are  the  salts  denominated  which  these  substances 
form  with  the  various  acids  ? 

QUESTIONS  ON  THE  VEGETABLE  ACIDS. 

[$}  320.]  By  what  means  are  the  vegetable  acids  dis- 
tinguished from  the  neutral  or  unsalifiable  vegetable  sub- 
stances ?  In  what  state  do  they  occur  ? 

A.     Fixed  Vegetable  Acids. 

[§  321.]  By  what  properties  are  the  fixed  vegetable 
acids  generally  distinguished?  What  are  the  most  re- 
markable vegetable  acids  ? 

[§  322.1  In  what  plants  does  tartaricacid  occur  in  i^s 
simple  form  ?  From  what  other  substaroe  may  it  yet  be 
obtained  ?  In  what  way  ?  What  sort  of  salt  does  tartaric 
acid  form  when  united  with  the  alkalies  ?  How  is  this 
salt  obtained? 

28 


RECAPITULATION 

What  sort  of  substance  is  bi-tartrate  of  potash,  or 
tartar  ? 

[§  323.]  Where  does  citric  acid  occur  ?  How  may  it 
be  produced  by  art?  In  what  way  is  it  commonly  obtain- 
ed? Into  what  substance  does  citric  acid  become  con- 
verted when  slowly  heated  with  alcohol  ?  WThat  are  the 
salts  called  which  citric  acid  forms  in  combination  with 
the  different  salifiable  bases  ? 

[§  324.]  In  what  vegetable  substances  does  malic  acid 
occur  ?  From  what  kind  of  berries  is  it  commonly  ex- 
tracted ?  What  are  its  properties?  What  are  the  salts 
called  which  it  forms  in  combination  with  the  salifiable 
bases  ? 

[§  325.]  What  are  the  properties  of  oxalic  acid  ? 
What  class  of  salts  does  it  form  with  the  different  salifiable 
bases  ?  What  are  the  most  remarkable  salts  belonging 
to  that  class  ? 

[§  326.]  In  what  substances  is  gallic  acid  contained? 
In  what  way  is  it  chiefly  obtained  ? 

What  are  the  principal  properties  of  gallic  acid  ?  What 
sort  of  precipitate  is  obtained  from  a  saturation  of  gallic 
acid,  with  carbonate  of  potash,  or  muriate  of  tin  ?  Of 
what  is  gallic  acid  a  principal  ingredient  ? 

[§  327.]  How  is  vegetable  jelly  obtained  ?  How  may 
it  be  purified  ?  What  shape  does  it  exhibit,  when  dry  ? 
What  kind  of  taste  has  it  in  a  slate  of  moisture  ?  With 
what  substances  does  it  combine  ? 

[§  328.]  From  what  substances  is  bitumous  acid  pro- 
duced ?  What  properties  does  this  acid  possess,  when 
perfectly  dry  ?  Into  what  substances  does  it  become  de- 
composed by  dry  distillation  ? 

During  what  other  process  is  bitumous  acid  produced  ? 

[§  329.]  Which  are  the  most  important  acids  belong- 
ing to  the  class  of  vegetable  acids,  capable  of  sublimation  ? 
Where  are  these  acids  found  ?  How  may  they  be  ob- 
tained ? 


OF    CHAPTER     V 


327 


330.]     Where  does   benzole  acid  occur  ?     In  what 
way    s  it  generally  obtained  ?     What   are   its  properties  1 


What  class  of  salts  does  it  form 
mineral  alkalies  and  oxides? 


in   combination  with  the 


[§  331.]  Where  does  succinic  acid  occur  ?  By  what 
means  may  it  be  produced  ?  What  are  its  properties  1 
What  class  of  salts  does  it  form  with  the  mineral  and  vol- 
atile alkalies? 

[§  332.]  From  what  substance  is  boletic  acid  obtain- 
ed ?  What  are  its  properties  ? 

[§  333.]  What  acids  belong  to  the  liquid  vegetable 
acids  ?  Where  do  Prussic  and  cyanic  acid  occur  1  What 
do  these  two  acids  seem  to  be  ?  Of  what  elements  are 
they  compounded  ? 

[§  334.]  Where  does  acetic  acid  occur  ?  By  what 
other  processes  is  it  formed  ?  Of  what  substance  does 
acetic  acid  form  the  principal  ingredient?  What  is  the 
composition  of  vinegar  ? 

How  is  vinegar  prepared  ?  What  sort  of  residue  is  obtain- 
ed when  vinegar  is  distilled  to  thickness  ?  By  what  means 
may  vinegar  be  rectified  (made  stronger)  ? 

What  are  the  principal  properties  of  acetic  acid  ?  What 
class  of  salts  does  it  form  with  the  mineral  oxides  ?  Which 
are  the  most  remarkable  of  these  salts  ? 

With  what  other  organic  substances  does  acetic  acid 
yet  combine  ?  In  what  consists  the  difference  between 
the  chemical  composition  of  vinegar  and  alcohol  ? 

[§  335.]  From  what  substances  may  Prussic  acid  be 
obtained?  What  does  Prussic  acid  yield  when  treated 
with  blood,  alum,  and  vitriol  of  iron  ? 

QUESTIONS  ON  VEGETABLE  SUBSTANCES  OF  AN  INDETER- 
MINED  NATURE. 

[§  336.]  Into  how  many  classes  may  all  vegetable  sub- 
stances of  an  indeterrnined  nature  be  divided?  What  are 
the  three  classes  ? 


328  RECAPITULATION. 

[§  337.]  Which  are  the  most  remarkable  coloring  mat- 
ters found  in  plants  ? 

What  are  those  dyeing  stuffs  called  which  are  soluble 
in  water,  or  dilute  spirits  of  wine  ?  What  colors  are  only 
entirely  dissolved  in  alcohol  ?  How  are  they  all  acted  up- 
on by  chlorine  and  muriatic  acid  ?  What  do  all  of  them 
leave  after  combustion  ? 

What  becomes  of  some  of  the  salts  when  mixed  with  differ- 
ent solutions  of  coloring  matter  ?  Which  salts  are  most  liable 
to  this  decomposition  ? 

[§  338.]  In  what  state  is  indigo  obtained  from  vege- 
tables ?  What  are  the  elements  of  the  different  kinds 
of  indigo? 

[§  339.]  How  were  the  different  vegetable  extracts 
formerly  divided  ?  What  substances  are  properly  called 
vegetable  extracts  ?  How  do  most  of  them  taste  1 

By  what  properties  are  they  all  more  or  less  distinguish- 
ed ?  Has  any  of  them  as  yet  been  obtained  in  its  simple 
form? 

[§  340.]  What  vegetable  substances  are  called  fer- 
mentous  principles?  Where  do  they  occur?  What  are 
their  properties  ?  Into  how  many  different  substances  may 
they  be  divided  ? 

[§  341.]  What  are  lees  or  dregs  ?  What  sort  of  mass 
do  they  form  ?  What  are  the  properties  of  this  mass  ? 

[§  342.]  What  sort  of  substance  is  vegetable  albumen? 
In  what  way  may  it  be  obtained  ?  What  does  it  form  when 
heated  or  boiled  ?  What  properties  does  it  possess  when 
perfectly  dry  ? 

[§  343.]  How  is  gluten  obtained  ?  What  are  its  prop- 
erties ?  Into  what  three  distinct  substances  does  it  be- 
come decomposed,  when,  in  a  state  of  moisture,  it  is  boiled 
in  alcohol  ? 

Why  does  gluten  belong  to  the  most  important  vegeta- 
ble substances  ? 


ANIMAL    CHEMISTRY. 


CHAPTER     VI. 


ANIMAL  CHEMISTRY.* 

§  344.  Ingredients  of  the  Animal  Body.  The  ani- 
mal body  consists,  like  the  plant,  of  immediate,  more  re- 
mote, and  ultimate  chemical  ingredients.  The  immediate 
ingredients,  which  are  discovered  by  the  chemical  inves- 
tigation of  animal  substances,  are 

1 .  Gaseous  ;  viz  :     Carbureted  hydrogen  gas,  Carbonic 
acid  gas,  Nitrogen,  Oxygen,  &c. 

2.  Liquid;  like  the  Gastric  juice  of  the  stomach,  Sa- 
liva, mucilage,  bile,  chyle,  blood,  milk^&LQ. 

3.  Soft,  and  easily  melting.    To  these  belong  the  greasy 
substance  in  the  joints,  the  marrow,  the  fat,  the  humors  of 
the  ear  and  eyes,  &c. 

4.  Soft  and  Elastic ;  like  the  muscles,  the  flesh,  liga- 
ments, tendons,  the  membranes,  cartilage,  hair,  scales,  fea- 
thers, wool,  &c. 

5.  Hard;  the  bones,  horns,  and  hoofs  of  animals,  the 
elates,  and  nails,  and  the  coverings  of  insects. 

§  345.     These   ingredients  of  the  animal  body,  may, 

*  We  shall  not  dwell,  here,  upon  the  principal  difference  between 
plants  and  animals,  which  undoubtedly  consists  in  sensation  and  lo- 
comotion of  the  latter.  This  is  a  more  proper  subject  for  Natural 
History  and  Physiology.  Chemistry  treats  only  of  the  combination 
and  analysis  of  substances,  as  far  as  the  elements  of  matter  are  con- 
cerned, and  with  regard  to  these,  the  remarks  made  on  the  compo- 
sition of  vegetables,  (§  297  —  301),  apply  equally  to  that  of  an- 
imals. 

28* 


330  ANIMAL    CHEMISTRY. 

like  those  of  the  plants,  be  divided  into  combustible  and 
incombustible  substances.  The  combustible  ones  are  again, 

1.  Neutral ;  in  which  the  hydrogen  is  to  oxygen  in  the 
same  proportion  as  in  water,  (as  1  to  8),  like  the  sugar  of 
milk. 

2.  Watery  ;  in  which  the  hydrogen  is  to  the  oxygen  in 
a  larger  proportion  than  in  water,  (in  a  larger  proportion 
than  1  to  8),  like  the  oils  and  fats. 

3.  Acetous  ;  in  which  the  hydrogen  is  to  the  oxygen  in 
a  less  proportion  than  is  necessary  to  form  water,  (in  a  less 
proportion  than  I  to  8).     To  this  class  belong  the   animal 
acids. 

4.  Undetermined;  like  fibrin,  glutin,  cheese,  &c. 
The  incombustible  animal  substances,  which  remain  as 

ashes  at  the  combustion  of  those  we  have  just  enumerated, 
are  either  oxides  or  salts.  The  principal  oxides  obtained 
by  the  combustion  of  animal  matters,  are  soda,  silicons 
earth,  oxide  of  iron,  and  of  manganese.  The  salts  produ- 
ced in  the  same  manner  are  carbonate  of  lime,  and  potash, 
muriate  of  soda,  (chloride  of  potassium),  sulphate  of  lime, 
and  phosphate  of  lime  and  magnesia. 

§  346.  The  ultimate  principles  or  elements  of  the 
animal  body  are  the  same  as  those  of  the  plants  ;  viz  ;  hy- 
drogen, oxygen,  carbon,  and  nitrogen;  to  which  may  be 
added  a  small  proportion  of  sulphur,  phosphorus,  magne- 
sium, and  iron  ;  but  the  proportion,  in  which  these  ele- 
ments are  combined,  are  essentially  different  from  those  in 
which  they  are  compounded  in  vegetables.  That  nitrogen 
enters  much  more  into  the  composition  of  animal  sub- 
stances than  it  does  in  that  of  vegetables,  is  sufficiently 
evident  from  the  highly  offensive  smell  which  accompanies 
their  spontaneous  decomposition,  owing  to  the  ammonia,  (a 
compound  of  nitrogen),  and  sulphureted  hydrogen,  which 
are  then  given  off  in  great  quantities. 

Among  the  various  parts  of  which  the  animal  body  is  com- 
posed, those  enumerated  in  §344  and  §345  are  by  far  t' c 
most  interesting  ;  we  shall  proceed  now  to  describe  those 
among  them,  a  knowledge  of  which  is  indispensable  to  a  proper 
understanding  of  our  own  physical  organization. 


ANIMAL  JELLY. -ALBUMEN.  331 

1.     Animal  Jelly,  (Glue). 

$  347.  Animal  Jelly,  or  glue,  (or  at  least,  a  substance 
which  by  boiling  with  water  becomes  changed  into  jelly),* 
composes  the  cellular  membranes,  the  skin,  ligaments,  and 
tendons,  as  well  as  the  cartilage,  and  the  cartilaginous 
parts  of  the  bones  of  most  animals.  It  is  obtained  chiefly 
by  boiling  these  substances,  (more  especially  the  skins  and 
bones)  for  a  considerable  time,  after  having  previously 
washed  them  with  cold  water.  It  possesses  generally  a 
pale  yellowish  color,  and  is  semi-transparent  and  elastic  ; 
but  when  dry,  it  is  solid,  brittle,  and  of  a  lamellar  texture. 
It  is  specifically  heavier  than  water,  without  taste  or  smell, 
and  does  in  no  way  effect  vegetable  colors.  A  solution  of 
animal  glue,  or  the  gelatinous  substance  it  forms  with  wa- 
ter, soon  undergoes  spontaneous  decomposition,  accom- 
panied by  a  fetid  smell,  produced  by  the  ammonia  which 
is  given  off  during  this  process. 

The  connecting  power  of  glue  is  weakened  by  boiling  ;  but 
its  solubility  is  thereby  increased.  When  submitted  to  dry 
distillation,  it  is  decomposed  into  a  highly  inflammable  gas,  car- 
bonate of  ammonia,  a  brown  watery  liquid,  (spiritus  cornu 
cervi),  a  brown  sort  of  tar,  and  a  quantity  of  animal  charcoal, 
which,  however,  is  less  combustible  than  vegetable  charcoal, 
on  account  of  the  nitrogen  which  it  contains. 

Gelatine  (animal  glue  mixed  with  water)  is  also  soluble  in 
the  acids,  and  in  solutions  of  pure  alkalies.  It  combines  with 
muriatic  and  several  other  dilute  acids,  and  with  a  variety  of 
mineral  bases  and  salts. 

2.     Albumen. 

§  348.  This  substance  occurs  in  the  eggs  of  birds, 
lizards,  fishes,  and  insects  ;  in  the  chyle,  the  blood,  and 
in  several  secretions  of  the  animal  body.  Of  its  occur- 
rency  in  the  vegetable  kingdom  we  have  already  spoken 
n  the  preceding  chapter,  (§  342).  The  white  of  eggs 
contains  much  pure  albumen,  mixed,  however,  with  acon- 

*  Many  distinguished  philosophers  deny  the  existence  of  already 
formed  jelly  in  the  animal  body  ;  but  consider  it  as  a  product  of  a 
gluey  substance  boiled  with  water. 


332  BLOOD. 

siderable  portion  of  water.     By  evaporating  this,  albumen 
is  obtained  in  a  solid  state. 

Properties.  When  albumen  is  exposed  to  a  temperature 
of  about  174°  Fahrenheit,  it  becomes  converted  into  a 
white,  solid,  somewhat  elastic  mass  ;  which  when  perfectly 
dry,  changes  into  yellow,  becomes  hard  and  brittle,  is  in- 
soluble in  water,  and  resists  putrefaction  for  a  considerable 
length  of  time  ;  whereas,  in  a  coagulated  state,  it  speedily 
undergoes  spontaneous  decomposition.  A  solution  of  al- 
bumen in  water  coagulates  at  a  boiling  heat,  and  so  much 
is  this  a  characteristic  of  albumen,  that  even  a  solution  of 
one  single  part  of  it  in  one  thousand  parts  of  water,  be- 
comes opaque  at  a  temperature  of  212°  Fahrenheit.  When 
burned  in  an  open  fire,  it  emits  a  smell  like  burnt  feathers, 
and  leaves  charcoal.  From  a  solution  in  water,  it  may  be 
precipitated  by  nitric,  sulphuric,  and  muriatic  acid.  It 
combines  with  the  mineral  bases  and  salts,  and  with  lime 
forms  a  perfectly  solid  mass.  By  dry  distillation  it  is  de- 
composed into  its  elements,  hydrogen,  carbonic  acid  gas, 
prussic  acid,  water,  carbonate  of  ammonia,  nitrogen,  and 
carbon. 

3.     Blood. 

§  349.  This  liquid,  into  which  all  nutriment  is  con- 
verted, and  which  by  its  circulation  renews  constantly  the 
whole  organization  of  the  body,  consists  principally  of  three 
parts,  viz  :  1,  a  certain  fibrous  substance  termed  fibrin; 
2d,  of  albumen,  (which  is  the  cause  of  its  coagulation  by 
heat  and  the  acids)  ;  3d,  of  a  small  variable  proportion  of 
mineral  salts,  (chloride  of  sodium,  potassium,  phosphate  of 
lime,  &c.).  These  substances  have  for  each  other  but 
little  affinity  ;  for  in  a  very  short  time  after  blood  has  been 
drawn  from  the  vein,  it  coagulates,  that  is,  becomes  sepa- 
rated into  two  very  distinct  parts,  viz.  into  a  yellowish-green 
liquid,  which  exudes  from  below  the  surface,  the  scrum, 
and  a  remaining  solid  substance,  called  the  cruor. 

The  cerum  consists  of  a  solution  of  albumen,  gelatine, 
and  salt  of  sodium,  potassium,  and  magnesia.  The  cruor 
can,  by  washing  with  water,  again  be  separated  \niojibrin 


BLOOD.  — MILK.  333 

and  coloring  matter.  The  latter  ingredient  consists  of 
nearly  the  same  elements  as  albumen,  (see  the  preceding 
section),  with  an  almost  imperceptible  addition  of  oxide  of 
iron.* 

Chemical  Changes  in  the  Nature  of  Blood,  occasioned  by 
Respiration. 

§  350.  The  process  of  respiration  consists,  as  is  gen- 
erally known,  in  two  distinct  operations.  By  the  first, 
which  is  termed  inspiration,  a  certain  portion  of  atmosphe- 
ric air  is  taken  into  the  lungs,  which  after  coming  in  con- 
tact with  the  blood,  and  suffering  certain  chemical  changes, 
is  by  the  second  again  expelled.  The  changes  which 
atmospheric  air  undergoes  by  the  process  of  respiration, 
are  the  following  : 

1.  The  whole  volume  of  air  is  considerably  diminished. 

2.  The  quantity  of  oxygen  is  reduced. 

3.  It  receives  an  addition  of  vapors  of  water,  and,    in 
men,  also  of  nitrogen,  together  with  a  considerable  portion 
of  carbonic  acid  gas. 

The  changes  produced  in  the  blood  by  the  same  cause, 
consists  principally, 

1.  In  an  absorption  of  oxygen,"^ 

2.  In  a  diminution  of  carbonic  acid  and  water,  and 

3.  In  a  subsequently  lighter  color,  owing  to  the  dimi- 
nution of  carbon. 

An  account  of  the  absorption  of  oxygen  gas  (1)  the  process 
of  respiration  is  generally  called  the  oxidation  of  the  blood. 
Some  philosophers,  however,  call  it  the  de carbonization  of  the 
blood,  because  a  great  quantity  of  carbon  is  expelled.  How  far 
the  process  of  respiration  is  necessary  to  animal  life,  and  what 
important  end  in  the  constitution  of  man  and  animals  is  thereby 
answered,  is  a  subject  for  Physiology. 

4.     Of  the  Milk. 
§  351.     This  well  known  white  liquid,  which  exists  in 

*  See  Gmehlin's  Chemistry,  Heidelberg,  1830. 
t  Some  Philosophers  pretend  also  of  nitrogen. 


334  BUTTER.  —  CHEESE. 

the  breast  of  female  quadrupeds,  and  in  all  other  animals 
which  bring  forth  living  young  ones,  is  composed  of  the 
following  ingredients  : 

1.  Water,  (by  far  in  the  greatest  proportion). 

2.  A  small  portion  of  pure  acetic  acid. 

3.  A  fat  substance,  called  butter. 

4.  Animal  albumen. 

5.  Mucilage. 

6.  Sugar  of  milk  ;  and 

7.  A  small  proportion  of  salts  of  potash,  lime,  and  mag- 
nesia. 

These  substances  appear  to  be  partly  in  a  state  of  so- 
lution, and  partly  only  suspended  in  the  liquid.  When 
milk  is  boiled,  a  portion  of  its  animal  albumen  collects  at 
its  surface  in  form  of  a  pellicle,  (small  skin),  which  as  soon 
as  it  is  removed,  is  replaced  by  another.  If  it  falls  to 
the  bottom,  it  becomes  burnt,  and  imparts  to  the  milk  a 
peculiar,  disagreeable  taste.  It  is  probable  that  heated  milk 
would  entirely  coagulate,  like  albumen,  if  this  latter  sub- 
stance were  not  diffused  through  a  great  portion  of  water. 

5.  Butter. 

§  352.  If  milk  is  suffered  to  stand,  even  excluded 
from  the  atmosphere,  a  spontaneous  decomposition  takes 
place  —  an  oily  unctuous  substance  rises  to  the  top,  which 
is  called  cream.  This  is  by  agitation  (churning)  again 
separated  into  a  substance  called  butter,  and  a  thin  fluid 
resembling  milk  deprived  of  its  cream.  Butter  is  a  val- 
uable article  of  domestic  economy ;  possesses  generally  a 
yellow  color,  a  peculiar  agreeable  taste,  and  is  of  a  soft 
consistency.  When  melted,  which  may  be  effected  at  a 
temperature  of  98°  Fahrenheit,  it  becomes  transparent  ; 
but  its  taste  is  rendered  less  agreeable.  In  this  state,  or 
salted,  it  may  be  kept  much  longer  without  becoming  ran- 
cid, and  is  capable  of  transportation  by  sea. 

6.  Cheese. 

§  353.     When  milk  is  allowed  to  stand  until,  by  a  sort 


SUGAR     OF    MILK.  — ANIMAL    MUCUS.  335 

of  acetous  fermentation  (see  Chap.  VII.)  it  becomes  sour,  it 
coagulates,  and  forms  two  distinct  parts ;  viz.  the  curd, 
which  is  a  solid  substance,  and  a  liquid  called  whey.  The 
curd  of  milk,  pressed,  salted,  and  dried,  composes  cheese. 
The  whey,  a  thin,  transparent  fluid,  contains  still  a  portion 
of  curd  and  butter,  and  is  used  in  Switzerland  for  the  pre- 
paration of  certain  kinds  of  cheese. 

7.  Sitgar  of  Milk. 

§  354.  The  whey  of  milk,  when  separated  from  butter 
and  curd,  and  evaporated  at  a  gentle  heat,  yields  a  sub- 
stance called  sugar  of  milk.  This  is  a  solid  mass,  which 
is  readily  dissolved  in  water,  and  may  be  clarified  with  the 
white  of  eggs,  and  again  evaporated.  Upon  cooling,  it 
forms  regular  crystals  of  a  sweetish  taste,  which  are  insol- 
uble in  alcohol. 

Remark.  There  is  considerable  difference  between  the 
milk  of  different  animals.  Human  milk  is  sweeter  than  that  of 
cows,  but  yields  no  butter.  Goats1  milk  is  thick  and  fat,  and 
abounds  in  curd.  Its  butter  is  less  consistent  than  that  of 
cows'  milk;  but  it  contains  more  sugar  of  milk.  The  milk  of 
sheep  resembles  that  of  cows,  and  yields  the  greatest  quantity 
of  butter.  Mare's  milk  yields  hardly  any  butter,  or  cream. 
Jlsses'  milk  is  the  most  watery  of  all,  and  contains  the  least 
quantity  of  curd  and  butter. 

8.  Animal  Mucus. 

§  355.  This  substance  is  obtained  by  washing  mucus 
secretions  with  cold  water,  and  drying  the  parts  which  re- 
main undissolved.  It  is  transparent  and  brittle,  and  con- 
sists principally  of  carbonate  of  ammonia,  and  animal  oil. 
Together  with  water,  it  forms  the  principal  ingredient  of 
the  mucus  of  the  nose,  tears,  wind-pipe,  saliva,  and  bile, 
and  the  intestines. 

9.     Animal  Oils  and  Fats. 

§  356.  To  this  class  of  animal  substances  we  reckon 
chiefly  butter,  tallow,  lard,  wax,  and  spermaceti. 

Butter  and  wax  have  already  been  described,  (in  §352, 


ANIMAL,    ACIDS.— OLIFIC    ACID. 

§  316).  Fat  is  extracted  from  muscular  and  membranous 
substances,  by  exposition  to  a  gentle  heat.  Fat  thus  pu- 
rified is  called  lard  when  soft,  and  tallow  when  of  a  hard 
consistency.  It  has  an  insipid  taste,  and  when  perfectly 
pure  is  destitute  of  smell.  It  is  insoluble  in  water,  or  alco- 
hol, but  united  with  potash  or  soda,  forms  soap,  (see 
Chap.  Ill,  §  150).  By  long  keeping  it  becomes  rancid, 
which  is  probably  owing  to  its  combination  with  oxygen. 
The  fat  of  whales  is  obtained  in  a  liquid  state  as  an  oil. 
From  its  great  value  in  artificial  illumination,  it  is  an  ex- 
tensive article  of  commerce. 

Spermaceti  (sperm-oil)  is  chiefly  obtained  from  the  fat 
of  the  white  whale.  It  crystalizes  from  a  solution  in  hot 
alcohol  in  white  shining  leaves,  or  in  a  radiant  mass.  It 
melts  at  112°  Fahrenheit,  is  inodorous,  and  has  no  action 
on  vegetable  colors.  It  is  extensively  used  for  the  manufac- 
ture of  candles. 

10.     Animal  Acids. 

§  357.  The  human  and  animal  body  contains  or  yields 
a  number  of  acids,  which  occur  in  the  mineral  and  vege- 
table kingdoms.  To  these  belong  the  phosphoric,  muri- 
atic, sulphuric,  carbonic,  acetic,  benzoic,  and  malic  acidsj 
all  of  which  have  already  been  described  in  the  preceding 
sections;  but  besides  these,  a  number  of  others,  which  are 
more  or  less  peculiar  to  animal  formation.  The  most  im- 
portantof  these  are  \heolific,  lactic,  mucous,  zndformic  acid. 

a.     Olific  Acid. 

^  353  This  acid  is  formed  in  the  bile  of  men,  bul- 
locks, swine,  and  bears;  also  in  old  tallow  and  cheese. 
It  crystalizes  in  white  needles,  a  little  before  the  freezing 
point  of  water,  to  a  colorless  or  yellowish  oil,  (hence  its 
name),  and  evaporates  under  the  recipient  of  an  air  pump, 
without  decomposition.  It  is  soluble  in  water,  has  a  faint 
rancid  taste  and  smell,  and  combines  with  the  mineral 
acids  and  bases. 


LACTIC,    MUCOUS,    AND    FORMIC    ACID.         337 

b.     Lactic  Acid* 

§  359.  Lactic  acid  is  found  in  its  simple  form,  or  united 
with  ammonia,  potash  and  soda,  in  almost  all  animal  parts 
and  liquids;  in  the  blood,  in  the  milk,  muscles,  &,c,  (see 
Chap.  VII).  It  is  also  produced  by  the  acetous  fermen- 
tation of  a  variety  of  vegetable  substances  ;  or  may  be  ob- 
tained from  sour  milk,  by  evaporating  it  to  about  £  of  its 
volume,  and  filtering  the  residue. 

Properties.  It  is  a  yellowish-brown  syrup,  incapable 
of  crystalization,  which  has  a  very  sour  taste,  and  deli- 
quesces at  the  atmosphere.  With  the  different  mineral 
alkalies  it  forms  a  kind  of  salt,  called  lactates.  These 
salts  are  soluble  in  water,  (some  of  them  also  in  alcohol), 
and  deliquesce  in  contact  with  air. 

d.     Mucous  Acid.     (  Saccho-Iactic  Acid.) 

§  360.  Mucous  acid  is  the  product  of  nitric  acid  dis- 
tilled with  sugar  of  milk,  or  vegetable  gum.  It  is  a  white, 
sandy  powder,  which  has  little  smell  or  taste,  and  reddens 
litmus  paper.  It  is  soluble  in  cold,  but  much  better  in 
warm  water.  When  heated,  it  melts  with  a  brown  color, 
and  becomes  partly  decomposed  into  carbureted  hydro- 
gen gas,  carbonic  acid,  acetic  acid,  and  a  sort  of  charcoal 
of  a  metallic  lustre.  In  a  red-hot  crucible  it  burns  like 
oil.  With  the  mineral  bases  it  combines  to  a  kind  of  salts, 
which  are  called  saccho-lactales. 

e.     Formic  Acid. 

§  361..  The  acidity  of  ants  is  taken  advantage  of,  by 
distilling  them  with  water,  by  which  means  a  peculiar  acid 
is  obtained,  which  has  received  the  name  of  formic  acid, 
(from  a  peculiar  kind  of  ants  called  formica  rufa). 

Properties.  Concentrated  formic  acid  does  not  congeal 
at  any  degree  of  artificial  cold,  although  it  is  specifi- 
cally heavier  than  water.  It  has  a  peculiar  pricking,  sour 

*  The  two  celebrated  chemists,  Fourcroi  and  Vauquelin,  first  dis- 
covered this  acid  in  the  amnios  of  cows  ;  hence  its  name. 

29 


SALIVA.  — GASTRIC    JUICE BILE. 

taste,  may  be  mixed  with  water  in  all  proportions,  and 
combines  with  the  mineral  alkalies  to  a  kind  of  salts, 
called  formiates. 

11.      Of  the  Different  Liquids  employed  in  the  Process  of 
Digestion. 

§  362.  The  principal  liquids  and  secretions  which  are 
subservient  to  the  process  of  digestion,  are  the  saliva,  the 
gastric  juice,  and  the  bile. 

a.     Saliva. 

§  363.  This  is  a  liquid  secreted  by  certain  glands,  and 
brought  into  the  mouth  to  be  mixed  with  the  food  during 
mastication.  It  is  transparent,  gradually  deposing  its  mu- 
cous, inodorous,  and  nearly  of  the  same  specific  gravity  as 
water.  The  saliva  of  men  produces  generally  a  weak,  al- 
kaline effect  on  vegetable  colors,  (reddens  litmus  paper). 
During  some  diseases  the  saliva  is  sour,  and  forms  with 
nitric  acid  a  transparent  pellicle.  It  is  principally  com- 
posed of  water,  mucous,  albumen,  chloride  of  potassium, 
and  phosphate  of  lime,  soda,  and  ammonia. 

b.     Gastric  Juice. 

§  364.  This  liquid  issues  from  the  inner  coats  of  the 
stomach,  and  serves  in  the  process  of  digestion,  as  a 
most  powerful  solvent.  It  contains,  besides  several  animal 
substances,  such  as  mucous,  albumen,  saliva,  &c,  muriatic 
and  acetic  acid,  together  with  chloride  of  potassium,  and 
sodium.  The  gastric  juice,  thrown  up  by  vomiting,  is 
very  much  similar  to  saliva ;  and  it  is  therefore  the  opinion 
of  some  celebrated  physiologists,  that  the  true  gastric  juice 
is  only  a  secretion  in  the  stomach,  through  the  irritation 
produced  by  the  food.  Its  solvent  power  is  so  great,  that 
after  death  the  stomach  itself  is  corroded  by  it. 

c.     Bile. 
§  365.     The   bile  of  a  healthy   man  has  generally  a 


CHYLE.  339 

greenish-brown  color,  a  bitter,  nauseous  taste,  and  is  sel- 
dom very  clear  or  transparent,  because  a  yellow,  insoluble, 
mucous  substance  'is  suspended  in  it.  It  is  decomposed 
by  all  the  acids,  whereby  a  large  proportion  of  albumen 
and  resin  is  deposited. 

Human  bile  consists  principally, 

1.  Of  a  very  bitter  resin,  which  is  the  yellow  substance 
suspended  in  it,  to  which  we  have  just  alluded. 

2.  Of  albumen. 

3.  Of  soda,  through  whose  agency  the  yellow  resin  is 
kept  in  a  liquid  state. 

4.  Of  mineral  salts,   phosphate  and  sulphate  of  soda, 
chloride  of  sodium,  and  oxide  of  iron ;  and 

5.  Of  a  large  proportion  (about  91  per  cent)  of  water. 

In  sick  persons  the  resinous  substance  suffers  consider- 
able diminution,  which  gives  the  bile  nearly  the  same 
appearance  as  albumen. 

The  bile  of  oxen,  calves,  sheep,  dogs  and  cats  consists  of 
resin,  a  sweet,  sugary  substance  ;  a  peculiar  yellow  body, 
composed  of  raucous  and  brown  coloring  matter,  pure  soda, 
phosphate  and  sulphate  of  soda,  chloride  of  sodium,  phosphate 
of  lime,  and  even  traces  of  phosphate  of  iron. 

12.     Of  the  Chyle. 

§  366.  By  the  digestion  of  food  in  the  stomach,  a  white 
juice  is  formed,  which  is  afterwards  yielded,  and  converted 
into  blood,  through  which  the  whole  body  receives  its  nu- 
triment. The  chyle  of  amimals,  4  or  5  hours  after 
taking  food,  possesses  a  perfectly  white  color,  is,  on  ac- 
count of  its  fat,  more  or  less  opaque,  and  has  a  saltish, 
sometimes  sweetish  taste.  It  is  specifically  heavier  than 
water  ;  but  lighter  than  blood.  (If  a  person  be  bled  4  or 
5  hours  after  taking  food,  a  small  portion  of  chyle  will 
float  on  top  of  the  coagulated  blood).  It  produces  a  weak 
alkaline  effect  on  the  color  of  violets,  which  is  changed 
into  green  (see  Intro,  page  38).  In  about  ten  minutes 
after  being  taken  from  the  Thoracic  duct,  it  becomes  of 
the  consistency  of  jelly,  and  in  course  of  24  hours  separates 
into  two  parts,  viz  :  into  a  solid  coagulum,  and  a  serous, 


340  BRAIN    AND    NERVES. 

colorless  liquid,  similar  to  that  obtained  by  the  spontane- 
ous decomposition  of  blood  (§  349).  The  coagulum  has 
a  strong  resemblance  to  cheese,  while  the  serous  part, 
dissolved  in  water,  has  a  sweet  taste,  somewhat  like  milk, 
to  which  the  whole  substance  of  the  chyle  is  more  or  less 
analogous. 

Dry  chyle,  when  burnt,  yields  32  per  cent  of  ashes, 
consisting  of  carbonate  of  soda,  chloride  of  potassium,  a 
little  potash,  and  phosphate  of  lime. 

13.     Substance  of  the  Brain  and  Nerves. 

§  367.  The  brain  of  men  and  quadrupeds  consists  of 
a  soft,  medullary  substance,  which  undergoes  spontaneous 
decomposition  when  exposed  to  the  air,  and  gives  off  a  pe- 
culiar acid  before  it  undergoes  putrefaction.  It  consists, 

1st.  Of  a  brownish-red,  liquid  fat,  which,  by  its  combus- 
tion, yields  phosphoric  acid. 

2d.  Of  a  more  solid  lamellar  fat  (wax),  peculiar  to  the 
brain. 

3d.    Of  phosphorus  contained  in  these  fats. 

4th.  Of  an  animal  extract  called  osmazome. 

5th.  Of  animal  albumen. 

6th.  Of  water,  and 

7th.  Of  a  number  of  mineral  salts,  chloride  of  sodium, 
phosphate  of  potash,  of  lime,  of  magnesia. 

Nerves.  The  nerves  of  men  contain  less  liquid,  than 
the  brain,  but  more  lamellar  fat  (wax  of  the  brain),  togeth- 
er with  a  much  larger  portion  of  albumen. 

The  brain  of  a  calf,  or  of  an  ox  is  of  a  greyish  color  ;  its 
fat  is  more  greasy  than  crystaline,  and  it  contains,  besides 
the  substances  enumerated  in  the  human  brain,  a  consid- 
erable quantity  of  phosphate  of  ammonia  with  traces  of 
iron.* 

*  The  analysis  of  a  peculiar  substance  found  in  the  brain  of  an  id- 
iot yielded  6  percent  white  tallow,  half  coagulated  albumen,  and  a 
peculiar  cartilaginous  matter,  which  was  insoluble  in  water.  See 
Gmehlen's  Chemistry,  Vol.  III. 


FIBRIN.  — BONES,   TEETH,   AND  CARTILAGE.    341 

14.     Fibrin  (Animal  Gluten). 

§  308.  This  substance  forms  the  principal  ingredient 
of  the  muscular  and  fleshy  parts  of  animals.  It  may  be 
procured  in  its  simple  form  in  two  different  ways. 

1st.  By  washing  meat  or  flesh  cut  up  into  small  pieces 
with  cold,  and  afterwards  with  warm  water;  and 

2d.  By  frequent  ablutions  of  the  coagulum  of  blood  on 
a  linen  strainer,  until  nothing  but  a  white,  fibrous  matter 
remains. 

Properties.  Tn  a  state  of  moisture  it  is  a  semi-transpa- 
rent, elastic  substance  ;  but  when  dry  it  is  a  brown,  trans- 
parent, brittle  mass,  which  is  insoluble  in  cold  water  ;  but 
gives  to  boiling  water  a  milky  color.  It  is  specifically 
heavier  than  water,  and  possesses  neither  taste  nor  smell. 
It  consists  principally  of  carbon,  oxygen,  nitrogen,  and 
only  a  small  proportion  of  hydrogen  gas. 

15.      Of  the  Bones,   Teeth,  and  Cartilage. 

§  369.  The  bones  and  teeth  of  animals  are  composed 
partly  of  earthy  salts,  which  give  them  solidity  and  hard- 
ness, and  partly  of  animal  matter,  which  serves  for  the 
purpose  of  cement,  and  keeps  the  earthy  ingredients  in  a 
state  of  union.* 

All  bones  contain  a  portion  of  cartilaginous  gelatine  ; 
but  the  harder  they  are  the  less  they  possess  of  this 
substance.  When  bones  are  boiled  for  a  considerable 
time  in  water,  the  cartilaginous  matter  is  extracted  from 
them  in  form  of  animal  glue.  Cold  muriatic  acid  dissolves 
even  their  salts,  and  leaves  them  in  a  state  of  soft  transpa- 
rency, preserving  still  their  natural  shape  and  figure. 

This  state  seems  to  be  the  first  stage  of  organized  bones,  and 
it  is  well  known  that  the  bones  of  infants  and  children  partake 
more  or  less  of  this  nature,  until  by  the  growth  of  the  individ- 
ual they  become  gradually  harder,  and  finally  obtain  that  firm- 
ness which  they  have  in  adults. 

Bones  are  entirely  dissolved  in  hot  muriatic  acid ;  from 
which,  by  adding  ammonia,  a  precipitate  may  be  formed, 

*  Henry's  Chemistry,  Vol.  II,  page  366. 
29* 


342         MARROW.— MUSCLES,  MEMBRANES,   &c. 

consisting  of  a  great  proportion  of  animal  glue,  and  phos- 
phate of  lime.  By  dry  distillation  they  yield  the  same 
product  as  animal  jelly  ;  but  leave  a  peculiar  kind  of  char- 
coal (bony  charcoal)  consisting  of  a  mixture  of  animal  coal, 
and  salts  of  magnesia  and  lime. 

§  370.  The  teeth  and  the  enamel  with  which  they  are 
covered  agree,  in  the  main  point,  with  the  construction  of 
the  bones  ;  but  they  contain,  besides,  as  a  basis,  a  pecu- 
liar animal  substance,  of  which  the  enamel  seems  to  be 
destitute. 

According  to  the  experiments  made  by  the  celebrated  Dr 
Antenrieth  of  the  university  of  Tubingen,  the  bones  of  chil- 
dren contain  about  2  per  cent  of  benzoic  acid  (see  §  339).  Upon 
growing,  this  acid  is  expelled  ;  but  occurs  again  (about  1  per 
cent),  in  old  men,  and  is  sometimes  the  cause  of  obstinate  dis- 
eases. 

Cartilage,  when  boiled  for  some  time  in  water,  becomes 
entirely  dissolved,  the  product  being  animal  glue  or  jelly. 

16.     On  the  Marrow. 

$  371.  This  substance  is  lodged  in  the  hollow  parts  of 
the  long  bones  ;  and  consists  chiefly  of  membranes,  fat, 
and  red  serum.  The  oily  substance  contained  in  most  hard 
and  solid  parts  of  the  bones  (Dipple's  oil),  consists  merely 
of  fat  and  serum.  It  was  formerly  used  in  medicine. 

17.     Of  the  Muscles,  Membranes,  Ligaments  and  Tendons. 

§  372.  It  is  highly  probable  that  muscular  flesh  con- 
sists merely  of  fibrin,  mixed,  however  with  fat,  blood, 
mucous,  and  nerves.  When  washed  with  cold  water  it 
yields  albumen,  saliva,  osmazom  and  salts.  When  boiled 
in  water,  it  yields  glue  or  fat,  the  residue  being  nearly 
all  fibrin,  which,  when  burnt,  leaves  phosphate  of  lime  as 
ashes. 

§  373.  Membranes.  These  are  thin  transparent  sub- 
stances, destined  to  line  the  different  cavities  of  the  body, 
or  in  form  of  bags  to  contain  liquids.  They  are  generally 


COVERING    OF    ANIMALS. 


343 


soluble  in  water,  and  dissolve   into  animal  glue,  which 
proves  that  they  are  principally  composed  of  Gelatine. 

§  374.  The  tendons,  or  sinews  are  the  cords  which 
connect  the  muscles  with  the  bones.  Their  composition 
differs  from  that  of  muscular  flesh,  only  by  the  absence  of 
fibrin. 

^  375.  The  ligaments  are  the  strong  bands  by  which 
the  bones  themselves  are  tied  together.  They  are  less 
soluble  in  water,  and  when  dried  are  darker  and  less  trans- 
parent than  the  sinews.  The  rest  of  their  chemical  com- 
position is  similar  to  that  of  the  tendons. 

18.     Covering  of  Animals. 

To  these  belong  the  skin,  nails,  claws,  horns,  hair, 
bristles,  &-c  ;  feathers  and  wool. 

a.    Of  the  skin. 

§  376.  The  skin  is  composed  of  two  parts — an  external 
white  coat,  which  is  nearly  insensible,  and  is  called  the 
cuticle  or  epidermis  ;  and  an  internal  one,  which  is  endow- 
ed with  great  sensibility,  called  the  cutis  vera  (true  skin). 
Between  these  two  there  is  a  soft,  mucous  substance, 
called  the  rete  mucosum.  The  external  skin  (the  cuticle) 
is  insoluble  in  water  and  the  acids,  and  consists  chiefly  of 
the  same  substance  as  horn  (supposed  to  be  a  composition 
of  coagulated  albumen  and  animal  glue  or  gluten).  The 
external  skin  (cutis  vera),  on  the  contrary,  contains  a 
number  of  blood-vessels  and  nerves,  is  highly  elastic,  and 
may  by  boiling  water,  be  converted  into  animal  glue  ;  a 
proof  that  its  principal  ingredient  is  gelatine. 

This  is  the  reason  why  the  skins  of  animals  yield  glue,  and 
why,  by  the  process  of  tanning,  they  are  capable  of  being  con- 
verted into  leather;  because  tan,  when  poured  upon  animal 
glue,  renders  it  elastic  and  impenetrable  to  water. 

b.   Nails,  Claws,  Horns,  Hoofs,  Scales,  &c. 
§  377.     These  substances,  with  the  exception  of  the 


344  COVERING    OF    ANIMALS. 

scales  of  Ji shes,  (which  are  formed  of  layers  of  membranes 
and  phosphate  of  lime),  are  very  nearly  allied  together 
with  regard  to  their  chemical  composition.  Their  princi- 
pal ingredient  is  the  same  horny  substance  of  which  the 
exterior  skin  is  composed. 

Horns  of  oxen  contain  besides,  1  per  cent  of  fat  and  a 
peculiar  animal  substance  which  may  be  precipitated  by 
tan. 

The  hoofs  of  horses  contain  a  greater  proportion  of  salts, 
and  yield,  by  calcination,  4  per  cent  of  phosphate  of  lime. 

The  horns  of  stags  are  in  their  composition  similar  to 
bones,  but  they  contain  more  cartilage. 

c.    Hair,  Bristles,  Feathers,  Wool  and  Silk. 

§  878.  The  hair  of  man  consists  of  thin  tubes,  of  a 
brown,  horny  substance,  filled  with  a  fat  oil,  and  surround- 
ed on  the  outside  with  a  sort  of  tallow,  which,  according 
to  its  color,  gives  the  hair  a  black,  brown,  light,  and  even 
red  appearance.  Black  hair,  when  dissolved  in  hot  potash, 
leaves  a  blackish-green  residue  of  oil,  iron,  and  sulphur; 
red  hair  leaves  red  oil,  sulphur,  and  only  traces  of  iron. 
The  ashes  of  human  hair  consist  of  common  salt  (chloride 
of  sodium),  silicious  earth  and  oxide  of  manganese.  The 
hair  of  horses  leaves,  upon  calcination,  12  per  cent  of  phos- 
phate of  lime. 

§  379.  Bristles  consist  principally  of  the  same  sub- 
stance as  horn.  Feathers  are  supposed  to  resemble  hair 
in  their  chemical  composition.  The  quills  consist  of  pure 
coagulated  albumen.  Wool  consists  likewise  of  the  same 
substances  as  hair  or  bristles  ;  but  it  is  surrounded  by  a 
greasy  sweat,  composing  about  40  per  cent  of  its  whole 
weight.  (This  sweat  is  the  reason  why  wool  forms  soap 
with  the  pure  alkalies).  We  are  almost  entirely  ignorant 
as  to  the  chemical  composition  of  silk.  It  consists  of  a 
peculiar  gluey  substance,  of  wax,  and  a  small  quantity  of 
essential  oil.  Yellow  raw  silk  contains,  in  addition  to 
these  ingredients,  a  peculiar  resinous  substance. 


RECAPITULATION. 


345 


The  use  of  wool  and  silk,  in  the  manufactory  of  cloth 
and  silks,  is  as  well  known  as  the  application  of  the  other 
coverings  of  animals'  in  domestic  economy  and  the  arts. 


RECAPITULATION. 


Questions  for  Reviewing  the  most  important  Principles 
contained  in  Chapter  VI. 

[§  344.]  What  are  the  immediate  ingredients  which 
are  discovered  by  the  chemical  investigation  of  animal 
substances  ? 

[^  345.]  How  may  these  ingredients  be  again  divided  ? 
Into  what  four  classes  may  the  combustible  animal  sub- 
stances be  again  divided? 

What  are  the  incombustible  animal  substances  which 
remain  as  ashes,  at  the  combustion  of  those  which  you 
have  just  mentioned  ? 

[§  346.]  What  are  the  ultimate  principles  of  the  an- 
imal body  ?  How  do  we  know  that  nitrogen  enters  largely 
into  the  composition  of  animal  substances  1  To  what  is 
the  offensive  smell  owing,  which  accompanies  the  sponta- 
neous decomposition  of  animal  substances  1 

[§  347.]  What  sort  of  substance  is  animal  jelly  (or 
glue)  ?  How  is  it  obtained  ?  What  properties  does  it 
possess  ?  What  does  a  solution  of  animal  glue  or  jelly  in 
water,  soon  undergo  ? 

What  changes  does  glue  undergo  by  boiling  ?  Into  what 
substances  does  it  become  decomposed  by  dry  distillation  ? 
What  sort  of  animal  substance  is  Gelatine^  With  what  sub- 
etances  does  it  combine  ? 

[§  348.]  Where  does  animal  albumen  occur  ?  What 
does  the  white  of  eggs  contain  ?  How  may  pure  albumen 
be  obtained  from  the  white  of  eggs  ?  What  are  the  most 
remarkable  properties  of  albumen  1  What  changes  does 


346  RECAPITULATION 

a  solution  of  albumen  in  water  undergo  at  a  boiling  heat  ? 
What  sort  of  smell  does  it  emit  when  burnt  at  an  open 
fire  ?  By  what  acids  may  it  be  precipitated  from  a  solu- 
tion in  water  ?  Into  what  elements  does  it  become  de- 
composed by  dry  distillation  ? 

[§  349.  Of  how  many  different  parts  does  blood  con- 
sist ?  Have  these  substances  much  affinity  for  each  other  ? 
How  is  this  ascertained  1 

What  are  the  ingredients  of  the  cerum  1  Into  what  two 
substances  may  the  cruor  be  again  separated  by  washing 
it  with  water  1  What  are  the  ingredients  of  the  coloring 
matter  of  blood  similar  to? 

[§  350.]  Of  how  many  distinct  operations  consists  the 
process  of  respiration  ?  In  what  consist  the  two  process- 
es ?  What  are  the  changes  which  atmospheric  air  under- 
goes by  the  process  of  respiration  ? 

What  are  the  changes  which  the  blood  itself  undergoes  ? 

What  is  the  process  of  respiration  also  called,  on  account  of 
the  absorption  of  oxygen  gas  ?  Why  do  some  philosophers 
call  it  the  decarbonization  of  the  blood  ? 

[§  351.]  What  are  the  principal  ingredients  of  milk  ? 
What  becomes  of  the  portion  of  albumen  contained  in  milk 
when  the  latter  is  boiled  ?  What  sort  of  taste  does  it  im- 
part to  the  milk,  when  it  falls  to  the  bottom  and  becomes 
burnt  ?  What  change  would  milk  undergo  by  the  process 
of  boiling,  if  it  did  not  contain  a  large  quantity  of  water  ? 

[§  352.]  What  becomes  of  milk  when  it  is  suffered  to 
stand  still,  even  when  excluded  from  atmospheric  air? 
What  is  the  oily,  unctuous  substance  called,  which  rises  to 
the  top  ?  Into  what  two  substances  is  cream  separated  by 
agitation  or  churning  1  What  are  the  principal  properties 
of  butter  ?  How  may  butter  be  preserved,  or  be  made  ca- 
pable of  transportation  by  sea  ? 

[§  253.]  Into  what  two  substances  does  milk  become 
decomposed,  when  suffered  to  stand  until  it  becomes  sour? 
What  substance  does  the  curd  of  milk  form  when  pressed, 
salted  and  dried  ?  For  what  purpose  is  the  whey  used  in 
Switzerland  ? 


OF    CHAPTER    VI.  347 

[§  354.]  What  substance  does  the  whey  of  milk  yield 
when  separated  from  butter  and  curd,  and  evaporated  at  a 
gentle  heat  ?  What'properties  does  sugar  of  milk  possess  ? 

What  difference  is  there  between  goats'  milk,  and  the  milk 
of  cows  ?  What  sort  of  milk  is  that  of  sheep  ?  What  sort  of 
milk  is  the  most  watery  of  all,  and  contains  the  least  quantity 
of  curd,  or  butter? 

[§  355.]  How  is  animal  mucus  obtained  ?  What  are 
its  properties  ?  What  is  its  principal  ingredient  in  com- 
bination with  water  ? 

[§  356.]  What  animal  substances  belong  to  the  ani- 
mal oils  and  fats  ?  From  what  substance  is  fat  extracted  1 
When  is  fat  called  lard  1  When,  tallow  ?  What  does 
fat  form  when  united  with  potash  or  soda  ?  What  becomes 
of  it  by  long  keeping  ?  In  what  state  is  the  fat  of  whales 
obtained  ? 

How  is  spermaceti  obtained  ?  What  are  its  properties  ?  For 
what  purposes  is  it  used  ? 

[§  357.]  What  acids  are  contained  in  the  animal  body 
that  occur  also  in  the  mineral  and  vegetable  kingdoms  ? 
What  other  acids  does  it  contain,  which  are  peculiar  to 
the  animal  kingdom  ? 

[§  358.]  Where  is  olific  acid  formed  ?  What  are  its 
properties '?  With  what  substances  does  it  combine  ? 

[§  350.]  Where  does  lactic  acid  occur?  By  what 
process  is  it  procured  ?  What  kind  of  salts  does  it  form 
with  the  mineral  alkalies  ?  What  property  do  these  salts 
possess  ? 

[^  360.]  What  sort  of  production  is  mucous  acid  ? 
What  are  its  properties  ?  To  what  kind  of  salts  does  it 
combine  with  the  mineral  bases  1 

[§  361.]  What  sort  of  acid  is  obtained  by  distilling 
ants  with  water  ?  What  are  the  properties  of  concentrated 
formic  acid  ?  What  sort  of  salts  does  it  form  with  the 
mineral  alkalies? 


348  RECAPITULATION 

[§  362.]  What  are  the  principal  liquids  employed  in 
the  process  of  digestion  ? 

[§  363.]  What  sort  of  liquid  is  saliva?  What  are  its 
properties  ?  What  effect  does  the  saliva  of  men  produce 
on  vegetable  colors?  What  changes  does  saliva  undergo 
in  certain  diseases  ?  What  are  its  principal  ingredients  ? 

[§  364.]  Whence  proceeds  the  gastric  juice,  and  in 
what  particular  process  does  it  act  as  a  solvent?  Of  what 
substances  is  it  composed  ?  To  what  is  the  gastric  juice 
which  is  thrown  up  by  vomiting  similar  ?  What  is  the 
opinion  of  some  physiologists  respecting  the  nature  of  gas- 
tric juice  ?  How  does  gastric  juice  operate  upon  the 
stomach  after  death  ? 

[§  365.]  What  are  the  properties  of  human  bile,  in  a 
state  of  perfect  health  ?  How  is  bile  affected  by  the  acids  ? 

What  are  the  principal  ingredients  of  human  bile  ? 
Which  of  these  ingredients  is  particularly  affected  by  sick- 
ness ? 

What  are  the  ingredients  of  the  bile  of  oxen,  calves,  sheep, 
dogs  and  cats  ? 

366.]  What  sort  of  juice  is  formed  by  the  digestion 
food  in  the  stomach  ?  What  properties  does  the  chyle 
of  animals  possess,  4  or  5  hours  after  taking  food  ?  How 
do  we  know  that  chyle  is  specifically  lighter  than  blood  ? 
How  does  chyle  affect  the  color  of  violets  ?  What  chang- 
es does  it  undergo  when  taken  from  the  thoracic  duct  ? 
What  are  the  properties  of  the  coagulum,  and  what  those 
of  the  serous  part  into  which  chyle  separates  ? 

What  are  the  ingredients  of  the  ashes,  produced  by 
burning  dry  chyle  ? 

[^  367.]  What  kind  of  substance  is  the  brain  of  men 
and  quadrupeds?  Of  what  ingredients  does  it  principally 
consist  ? 

In  what  respect  do  the  nerves  of  men  differ  from  the 
brain  ? 

What  difference  is  there  between  the  chemical  compo- 
sition of  the  brains  of  calves  or  oxen,,  and  that  of  men  ? 


of  foe 


OF    CHAPTER    VI.  349 

[$  368.]  What  kind  of  substance  is  fibrin  or  animal 
gluten  ?  In  what  vyays  may  it  be  produced  in  its  simple 
form  1  What  are  it's  properties  ?  Of  what  elements  does 
it  consist? 

[§  369.]  Of  what  substances  are  the  bones  and  teeth 
of  animals  composed  ?  What  do  all  bones  contain  ?  By 
what  means  may  the  cartilaginous  matter  be  extracted 
from  them  ?  How  are  bones  affected  by  cold  muriatic 
acid? 

What  changes  do  the  bones  of  children  gradually  undergo, 
until  they  grow  to  be  adults  ? 

How  are  bones  acted  upon  by  hot  muriatic  acid  ?  What 
substances  do  they  yield  by  dry  distillation  ? 

[^  370.]  What  is  the  chemical  composition  of  the 
teeth  and  the  enamel  similar  to  ? 

What  remarkable  discovery  did  Dr  Autenrieth,  df  Tubigen, 
make  with  regard  to  the  bones  of  children  and  old  men  ? 

Into  what  does  cartilage  become  changed  by  boiling  it 
for  some  time  in  water  ? 

[§  371.]  Where  is  the  marrow  seated  ?  Of  what  does 
it  principally  consist? 

[§  373.]  What  does  muscular  flesh  probably  consist 
of?  What  does  it  yield  when  mixed  with  cold  water  ? 
What  does  it  yield  when  mixed  with  warm  water  ? 

[§  373.]  What  kind  of  substance  are  the  membranes? 
What  property  do  they  generally  possess  ? 

[§  374.]  What  office  have  the  tendons  or  sinews  ?  In 
what  respect  does  their  composition  differ  from  muscular 
flesh  ? 

[§  375.]  What  sort  of  substance  are  the  ligaments  ? 
In  what  respect  does  their  chemical  composition  differ 
from  that  of  the  sinews  ?  What  is  the  rest  of  their  com- 
position similar  to  ? 

[§  376.]  Of  how  many  different  parts  does  the  skin 
consist?  What  is  the  name  of  the  external  white  coat 

30 


350  RECAPITULATION 

which  is  nearly  insensible  ?  What,  that  of  the  internal  one, 
which  is  endowed  with  great  sensibility  ?  What  kind  of 
substance  is  situated  between  these  two  ?  What  is  the 
composition  of  the  epidermis?  What  that  of  the  cutis 
vera  ? 

What  is  the  reason  that  the  skins  of  animals  yield  glue,  or 
are  capable  of  being  converted  into  leather  ? 

[§  377.]  W'hat  is  the  principal  ingredient  of  the  nails, 
claws,  horns,  hoofs  and  scales  ? 

What  do  the  horns  of  oxen  contain,  besides  the  sub- 
stance contained  in  the  nails  ? 

What,  the  hoofs  of  horses  ? 

What  substance  are  the  horns  of  stags  similar  to  ? 

[^  378.]  What  does  the  hair  of  man  consist  oft 
What  residue  does  black  hair  leave,  when  dissolved  in  hot 
potash  ?  What,  red  hair  ?  What  are  the  ashes  of  hu- 
man hair  composed  of?  What  do  the  hair  of  horses  leave 
upon  calcination  ? 

[§  379.]  What  are  bristles  composed  of?  What  is 
the  composition  of  feathers  similar  to?  What  do  the 
quills  consist  of?  Of  what  substances  does  wool  consist  ? 
What  is  the  chemical  composition  of  silk?  What  does 
yellow  raw  silk  consist  of? 


GERMINATION    OF    SEEDS.  351 


CHAPTER     VII. 

OP  THE  CHEMICAL  PROCESS  ACCOMPANYING  THE  DEVEL- 
OPMENT, LIFE,  AND  DEATH  OF  ORGANIZED  BODIES. 

A.     GERMINATION  OF  SEEDS. 

$  380.  From  the  experiments  which  have  been  made 
with  the  seeds  of  different  plants,  we  are  able  to  lay  down 
the  following  principles  : 

I.  No  seed  can  germinate  without  moisture.  Water 
alone,  however,  is  insufficient  for  this  purpose.  Seeds 
thrown  into  water  die,  and  become  putrid. 

2.  Atmospheric  air,  or  oxygen  gas,  must  have  an  uninter- 
rupted access  to  it. 

No  germination  takes  place  in  pure  carbonic  acid,  hydrogen, 
or  nitrogen  gas,  or  very  rarified  air.  But  these  gases  do  not 
destroy  the  seed ;  they  merely  prevent  its  development  into  a 
plant. 

3.  It  is  necessary  that  the  temperature  should  be  at  least 
above  the  freezing  point  of  water. 

Different  seeds  require  different  degrees  of  temperature  ; 
but  none  germinate  at  a  temperature  as  low  as  32°  Fahrenheit. 

B.     PROCESS  OF  NUTRITION  NECESSARY  TO  LIFE. 

§  381.  Both  plants  and  animals  have  certain  external 
organs,  which  enable  them  to  take  up  a  greater  or  less 
quantity  of  gases,  liquids,  and  even  solids,  destined  to 
serve  them  as  nutriment.  They  decompose  these  substan- 
ces into  their  chemical  ingredients,  appropriate  to  them- 


352  VINOUS    FERMENTATION. 

selves  a  certain  portion  of  them,  and  rid  themselves  of  the 
rest.  By  this  continued  process  of  absorption  and  expul- 
sion, the  whole  vegetable  and  animal  life  is  constantly 
renovated,  and  those  animal  products  produced,  which  we 
have  described  in  the  preceding  chapters. 

The  effect  of  atmospheric  air  on  the  organization  of 
plants  is  similar  to  that  produced  by  the  respiration  of  ani- 
mals, (see  §  350).  They  absorb  a  certain  portion  of  oxy- 
gen, and  yield  in  its  state  an  equal  volume  of  carbonic 
acid  gas. 

C.     OF  THE  SPONTANEOUS  DECOMPOSITION  OF  ORGANIC 
SUBSTANCES. 

§  382.  Every  organized  body,  immediately  after  its 
death  suffers  a  spontaneous  decomposition  of  its  chemical 
ingredients,  which  soon  or  late  become  dissolved  into 
their  elements.  With  regard  to  vegetables,  this  spontane- 
ous process  has  received  the  name  of  fermentation. 

$  383.  The  immediate  products  of  the  spontaneous 
decomposition  of  vegetables  differing  from  each  other  es- 
sentially in  nature  and  quality,  naturally  lead  us  to  sup- 
pose that  there  are  different  kinds  of  fermentation ;  but 
we  distinguish  more  especially  between  the  vinous  and 
acetous.  Both  kinds  require, 

1.  The  presence  and  joint  action  of  water. 

2.  An  uninterrupted  access  of  air,  (to  yield  a  sufficient 
quantity  of  oxygen). 

3.  A  proper  degree  of  temperature.     (A  very  high  tem- 
perature disturbs,  and  a  very  low  temperature  retards  the 
process  of  fermentation.) 

1.      Vinous  Fermentation. 

§  384.  The  product  of  this  fermentation  is  a  vinous, 
or  at  least  a  spirituous  liquid,  (wine,  beer,  cider,  &c  ) 
hence  its  name.  Sugar,  or  sugary  substances,  are  the 
only  vegetable  matters  capable  of  vinous  fermentation.  But 
for  this  purpose  they  need  the  assistance  of  the  ferment ous 
principles  of  lees,  albumen,  and  gluten. 


VINOUS    FERMENTATION.  353 

In  order  that  the  fermentous  principle  shall  act  upon 
the  sugar,  it  is  necessary  that  it  should  be  in  close  contact 
with  the  latter.  THis  is  the  reason  why  no  fermentation 
takes  place  in  the  grape  itself,  where  both  substances  are 
in  a  state  of  separation.  It  explains  also,  why  the  presence 
of  water  is  indispensable ;  because  by  dissolving  both  the 
sugary  and  the  fermentous  principle,  it  brings  both  sub- 
stances in  immediate  contact.  The  vinous  fermentation 
of  sugar  may  therefore  be  considered  as  the  result  of  its 
decomposition  by  the  fermentous  principle. 

Phenomena  accompanying  Vinous  Fermentation. 

§  3S5.  The  phenomena  which  accompany  the  vinous 
fermentation  of  vegetables,  are  the  following  : 

1.  As  soon  as  it  commences,  a  motion   is  perceived  in 
the  interior  of  the  liquid,  its  temperature  rises  by  several 
degrees,  and  it  becomes  turbid. 

2.  The   volume  of    the  liquid    is  increased;    a   thick 
scum  is  forming  on  its  surface,  and  a  very  considerable 
quantity  of  carbonic  acid  is  produced,  which  is  impreg- 
nated with  alcohol.     (Hence  we  infer  that  the  sugar  is  de- 
composed into  carbonic  acid  and  alcohol.)* 

3.  When  these   phenomena   have  continued  for  some 
time,  the  volume  of  the  liquid  contracts   again,  the   tem- 
perature is  diminished,  the  scum  disappears,  no  more  car- 
bonic acid  is  produced,  and  a  precipitate  is  formed,  which 
renders  the  liquid  clear  and  transparent. 

4.  Instead  of  the  sweet  taste  which  the  liquid  had  be- 
fore the  fermentation,   it  has   now  a  pungent   taste,    an 
aromatic  flavor,  its  specific  gravity  is  diminished,  and  it 

*  This  agrees  perfectly  with  the  analysis  of  sugar,  alcohol,  and 
carbonic  acid  : 

r.  C  3  equivalents  of  carbon, 
Sugar  consists  of  J  6   4   do  Of  oxygen. 

Carbonic  acid  consists  of  1  equiv.  of  carbon  and  4  of  oxygen, 
Alcohol  do  2     do      of  carbon  and  2  of  oxygen. 

Amounting  together  to  3  equiv.  of  carbon  and  6  of  oxygen, 
30* 


354  ACETOUS    FERMENTATION. 

possesses  intoxicating  qualities,  in  a  word  —  it  has  become 
transformed  into  wine. 

§  386.  Wine,  the  product  of  vinous  fermentation,  must 
be  considered  as  a  peculiar  substance,  the  various  kinds 
of  which  agree  in  the  following  characterizing  properties  : 

1.  All  kinds  of  wine  are  specifically  lighter  than  water, 
and  have  more  or  less  color. 

2.  All  of  them  have  a  peculiar,  pungent  taste,  and  an 
aromatic  flavor. 

3.  They  are  all  intoxicating  (in  a  greater  or  less  degree). 

4.  They  yield  alcohol  by  distillation. 

Most  of  the  properties  of  wine  are  probably  owing  to 
the  last  mentioned  circumstance,  for  which  reason  many 
distinguished  chemists  consider  alcohol  as  the  product  of 
vinous  fermentation. 

The  difference  in  taste,  color  and  intoxicating  effects  of  the 
various  kinds  of  wine  is  owing, 

1st.  To  the  greater  or  less  quantity  of  water  which  they 
contain. 

2d.  To  the  vegetable  acids  which  enter  into  their  chemical 
composition  —  (citric,  malic,  tartaric  and  acetic  acid  ;  which 
were  contained  in  the  liquid  either  before  or  during  fermen- 
tation). 

3d.  To  the  peculiar  nature  and  properties  of  the  coloring 
matter. 

4th.  To  the  quantity  of  sugar  ;  and 

5th.  To  the  proportion  of  mucilage,  gluten,  and  vegetable 
extract. 

Upon  this  last  mentioned  circumstance  depends  the  main 
difference  between  beer,  cider,  and  the  wine  of  grapes. 

2.     Acetous  Fermentation. 

§  387.  By  this  name  we  distinguish  that  kind  of  fer- 
mentation of  vegetable  matter,  the  product  of  which  is 
vinegar.  A  great  number  of  vegetable  substances,  partic- 
ularly the  different  kinds  of  gum  and  vegetable  extracts, 
are  capable  of  acetous  fermentation  ;  but  they  need  for 
this  purpose  in  addition  to  the  fcrmcntous  principles 
also  a  free  access  of  air,  to  absorb  a  sufficient  quantity  of 


PUTREFACTION.  355 

oxygen,  and  a  temperature  of  from  74  to  84  degrees  Fah- 
renheit. 

A  limited  portion  of  alcohol  seems  to  be  favorable  to  the 
process,  and  increases  the  quantity  of  vinegar;  but  the  pres- 
ence of  sugar  is  believed  to  be  a  considerable  obstacle. 

§  388.  The  phenomena  attending  the  acetous  fermen- 
tation are  similar  to  those  which  accompany  the  vinous 
decomposition  of  vegetable  substances  (see  the  last  section). 
They  consist  in  an  internal  movement,  increase  of  tem- 
perature, development  of  carbonic  acid,  formation  of 
fibrous  matter,  which  renders  the  liquid  turbid,  &,c  ;  but 
the  liquid  acquires  gradually  an  acid  taste  and  smell,  un- 
til it  becomes  changed  into  what  is  properly  called  vinegar. 
This  product  is  found  upon  distillation  to  be  nothing  else 
but  very  dilute  acetic  acid  (see  §  334),  mixed,  however, 
with  different  vegetable  substances,  such  as  gluten,  gum, 
vegetable  extract,  &c,  upon  which  depend  principally  the 
quality  and  kind  of  vinegar. 

It  has  already  been  mentioned,  that  acetic  acid,  the  prin- 
cipal ingredient  of  vinegar,  is  also  obtained  by  dry  distillation 
of  wood,  and  other  vegetable  and  animal  matter. 

3.      Of  the  Process  of  Putrefaction. 

§  389.  One  of  the  principal  characteristics  of  animal 
substances  is  their  spontaneous  decomposition  after  death, 
which  is  called  putrefaction.  This  is  a  process  analogous 
to  the  fermentation  of  vegetable  matter,  and  leads  to  the 
same  results  —  that  is,  to  a  complete  destruction  of  all 
chemical  combinations,  as  they  existed  in  the  animal  dur- 
ing its  life-time  ;  although  the  products  of  putrefaction  and 
the  phenomena  which  are  dependent  on  it,  are  essentially 
different  from  those  which  are  produced  by  the  fermenta- 
tion of  vegetable  substances. 

There  are  a  few  vegetables  capable  of  exhibiting  the  phe- 
nomena of  putrefaction.  These  are  in  their  nature  and  chem- 
ical composition  very  much  similar  to  animal  matter,  and  con- 
tain (like  cabbage)  a  considerable  portion  of  nitrogen.  It  is 
on  this  account  some  philosophers  speak  of  the  putrid  fermen- 
tation of  vegetables. 


356  PUTREFACTION. 

^  390.  The  conditions  under  which  putrefaction  takes 
place  are  the  same  as  those  which  are  indispensable  to  the 
fermentation  of  vegetables  —  viz  :  presence  and  coopera- 
tion of  water,  free  access  of  air,  and  a  proper  degree  of 
temperature. 

It  is  highly  probable  that  there  are  different  degrees  and 
kinds  of  putrefaction,  according  to  the  different  classes  and 
kinds  of  animals  ;  but  the  whole  process  has,  as  yet,  been  too 
little  investigated  to  describe  more  than  the  general  phenom- 
ena which  accompany  it. 

Putrefaction  with  free  access  of  Air. 

§  391.  The  putrefying  substance  (commonly  muscular 
flesh  and  meat)  assumes  first  a  peculiar  musty  appearance 
and  smell,  which  soon  afterwards  becomes  sour,  pungent, 
and  fetid.  Its  taste  becomes  exceedingly  nauseous  ;  the 
cohesion  of  its  particles  is  considerably  diminished,  the 
organic  texture  entirely  destroyed,  arid  the  whole  changed 
into  a  soft,  pappy  brown  (sometimes  greenish)  mass.  Car- 
bonic acid  gas  is  now  given  off  in  great  profusion  ;  but 
the  quantity  of  inflammable  (hydrogen)  gas  is  visibly  di- 
minished. By  degrees  the  fetid  smell  ceases  ;  the  mass 
obtains  again  a  certain  degree  of  solidity,  and  becomes 
converted  into  an  earthy  substance  of  a  blackish  color. 
This  is  the  end  of  the  whole  process. 

If  the  process  of  putrefaction  is  carried  on  with  a  small  quan- 
tity of  water,  a  great  portion  of  inflammable  gas  (carbureted 
hydrogen)  is  given  off.  If  much  water  be  added,  then,  very 
little  gas  is  developed  ;  but  the  water  assumes  an  insufferable 
fetid  smell.* 

Putrefaction  with  little  or  no  access  of  Air. 

§  392.  The  phenomena  accompanying  this  sort  of 
spontaneous  decomposition  of  animal  substances  are  en- 
tirely different  from  those  we  have  just  mentioned  ;  partic- 
ularly if  the  animal  body  be  also  secluded  from  day-light, 

*  The  cause  of  this  excessively  offensive  odor  is  not  yet  suf- 
ficiently ascertained.  The  formation  of.  carbureted,  phosphureted, 
aud  sulphureted  hydrogen  alone  cannot  account  for  this  phenomenon. 


RECAPITULATION.  357 

and  submitted  to  a  moderate  degree  of  temperature.  Pu- 
trefaction advances,  then,  but  very  slowly  ;  the  odor  which 
it  emits  is  musty,  but  not  fetid ;  and  the  whole  is  chang- 
ed into  a  blackish,  powdery  substance,  bearing  great  re- 
semblance to  animal  charcoal  At  the  same  time  a  con- 
siderable quantity  of  nitric  acid  is  formed. 

The  process  of  putrefaction  may  be  retarded  for  a  long  time 
by  the  assistance  of  alcohol,  the  acids,  some  of  the  salts,  the 
volatile  or  essential  oils,  and  by  the  exclusion  of  atmospheric  air. 
The  mummies  of  the  Egyptians,  and  the  anatomical  preparations 
which  are  kept  in  spirits  of  wine,  and  which,  in  this  state,  re- 
sist putrefaction  even  for  centuries,  are  sufficient  proofs  of  this 
assertion. 

§  393.  All  combustible  substances  contained  in  the 
animal  body  are  thus  subjected  to  destruction  by  water, 
air,  and  the  joint  operation  of  the  elements.  But  the 
products  of  their  spontaneous  decomposition  are  not 
entirely  lost;  they  serve  to  enliven  and  nourish  the 
vegetation  of  plants,  which,  in  their  turn,  afford  nutriment 
to  animals  ;  and  so  does  this  change  from  life  to  death  and 
decomposition,  and  from  decomposition  again  to  life  and 
death,  continue  to  set  the  springs  of  human  industry  in 
motion,  and  affords,  by  a  wise  distribution  of  Providence, 
the  means  of  our  nutriment  and  comfort. 


RECAPITULATION. 
Containing  Questions  for  Reviewing  Chapter  VII. 

[§  380.]     What  principles  are  we  enabled  to  lay  down 
from  experiment  respecting  the  germination  of  seeds? 

[§  381.]     What  are  all  animals  and  plants  provided 

with,  for  the  purpose  of  nutrition  ?     What  do  they  do  with 

he  substances  they  take  up   by  these  organs?      What 

end  is  attained  by  this  continued  process  of  absorption  and 

expulsion  ? 


358  RECAPITULATION 

What  is  the  effect  of  atmospheric  air  on  the  organiza- 
tion of  plants,  similar  to  1  Why  ? 

[§  382.]  What  change  does  every  organized  body 
suffer,  immediately  after  death  ?  What  is  this  process  call- 
ed with  regard  to  vegetables? 

[§  883.]  What  are  the  principal  kinds  of  fermenta- 
tion ?  What  do  both  kinds  of  fermentation  require  ? 

[<§  384.]  What  sort  of  product  is  produced  by  vinous 
fermentation  ?  What  vegetable  substances  are  alone  ca- 
pable of  vinous  fermentation  ?  What  assistance  do  they 
need  for  this  purpose  ? 

What  is  necessary  in  order  that  the  fermentous  princi- 
ple should  act  upon  the  sugar  1  What  is  this  the  reason 
of?  Why  is  the  presence  of  water  necessary  for  this  kind 
of  fermentation  ?  As  what,  therefore,  may  the  vinous  fer- 
mentation of  sugar  be  considered. 

[§  385.]  What  phenomena  accompany  the  vinous  fer- 
mentation of  vegetables  ? 

[§  386.]  What  characterizing  properties  have  all  kinds 
of  wine  ? 

To  what  peculiar  ingredient  of  wine  are  most  of  its  in- 
toxicating qualities  owing  ? 

What  are  the  causes  of  the  difference  in  taste,  color,  and 
intoxicating  effects  of  the  various  kinds  of  wine  ? 

On  what  depends  the  principal  difference  between  beer, 
cider,  and  the  wine  of  grapes? 

[§  387.]  What  do  you  understand  by  the  acetous  fer- 
mentation of  vegetable  substances  ?  What  vegetable  sub- 
stances are  capable  of  this  kind  of  fermentation  ?  What 
do  they  need  for  this  purpose,  in  addition  to  the  ferment- 
ous principle  ? 

Is  the  presence  of  alcohol  favorable  or  a  hindrance  to  acetous 
fermentation  ?  Is  this  also  the  case  with  sugar  ? 

[§  388.]  What  are  the  changes  produced  by  acetous 
fermentation  ?  What  is  this  product,  upon  distillation, 
found  to  be  composed  of? 


OF    CHAPTER     VII.  359 

[$  389.]  What  is  the  spontaneous  decomposition  after 
death  of  all  animal  substances,  called  ?  What  is  this 
process  analogous  to  ?  To  what  results  does  it  lead  ? 

What  vegetable  substances  are  capable  of  exhibiting  the 
phenomena  of  putrefaction  ?  What  is  this  sort  of  putrefaction 
of  vegetables,  by  some  philosophers  called  ? 

[§  390.]  What  are  the  conditions  under  which  putre- 
faction takes  place  ? 

[§  391.]  What  phenomena  accompany  the  putrefaction 
of  animal  substances  with  free  access  of  air. 

What  kind  of  gas  is  given  off,  when  the  process  of  putrefac- 
tion is  carried  on  with  a  small  quantity  of  water  ?  What  takes 
place  when  a  large  quantity  of  water  is  added? 

[§  392.]  What  phenomena  accompany  the  putrefaction 
of  animal  substances  with  little  or  no  access  of  air  ? 

By  what  means  may  the  process  of  putrefaction  be  retarded 
for  a  considerable  length  of  time  ? 


APPENDIX. 


ON    THE    STEAM    ENGINE. 

[!T  is  not  to  be  expected  that  a  complete  treatise  on  so  com- 
plicated a  machine  should  be  annexed  to  an  elementary  trea- 
tise on  Chemistry ;  but  an  acquaintance  with  its  principal 
parts  being  absolutely  indispensable  to  a  correct  understanding 
of  a  great  number  of  valuable  improvements  in  mechanics  and 
the  arts,  we  have  endeavored  to  give  to  the  learner  a  brief 
sketch  of  its  most  important  elements.] 

§  394.  We  have  already  had  occasion  to  allude  to  the 
elasticity  of  steam,  and  gave,  in  §  35,  Fig.  XCIV,  an  ex- 
ample of  its  power  to  raise  a  piston  that  shall  work  air- 
tight in  a  cylinder.  Now  it  is  easily  conceived  that  if  the 
piston  rod  is  attached  to  some  lever  or  wheel,  it  may  com- 
municate to  them  a  certain  force  or  motion,  which  by  a 
proper  arrangement  may  be  transferred  to  any  particular 
part  of  the  machine  where  we  wish  it  to  operate.  A  ma- 
chine constructed  for  this  purpose,  and  in  which  the  elas- 
ticity of  steam  is  employed  for  the  moving  force,  is  called  a 
steam  engine. 

§  395.  In  the  experiment  represented  in  Fig.  XCIV, 
page  84,  the  piston  is  only  forced  up  by  the  expansive  pow- 
er of  the  steam  ;  but  when  the  steam  is  condensed  and  a 
vacuum  created  under  the  piston,  it  is  the  pressure  of  the 
atmosphere  which  forced  the  piston  down  again.  En- 
gines constructed  upon  this  principle  are  called  atmos- 
pheric engines.  They  require  the  cylinder  to  be  cooled 
down  after  each  stroke  of  the  piston,  in  order  to  pro- 
duce the  necessary  condensation  of  the  steam,  and 


APPENDIX. 


361 


the  subsequent  creation  of  a  vacuum  for  the  moving  down 
of  the  piston.  This  is  naturally  the  cause  of  a  great  loss 
of  fuel,  because  each  new  stroke  of  the  piston  must  be 
produced  by  the  forming  of  a  fresh  quantity  of  steam,  and 
a  subsequent  condensation  of  it,  by  cooling  down  the  cyl- 
inder. Besides  this  inconvenience,  the  motion  of  an  at- 
mospheric machine  cannot  be  regulated  like  that  of.  the 
engine  we  are  about  to  describe. 

Fig.  CXXXVI. 


§  396.  Fig.  CXXXVI  represents  the  most  essential 
part  of  what  is  called  a  double  working  engine.  B  repre- 
sents a  section  of  the  boiler,  provided  with  a  safety- 
valve,  in  order  to  admit  of  the  passing  of  the  steam  in  case 
its  elastic  force  should  endanger  the  safety  of  the  machine. 
The  pressure  upon  this  valve  may  be  regulated  by  the 
movable  weight  D,  suspended  from  the  end  of  the  lever 
D  E.  V.U  S  T  represents  the  barrel  or  cylinder,  to  which 
the  piston  R  is  fitted  in  such  a  way  as  to  admit  of  its 
moving  up  and  down,  without  allowing  the  least  quantity  o 
water  or  steam  to  escape  between  it  and  the  barrel.  To  the 
piston  is  attached  the  piston-rod  R  K,  which  is  also  made 
cylindrical,  and  is  kept  air  and  steam  tight  by  the  stuffing- 
box  K,  made  of  leather  and  stuffed  with  wool,  tow,  or  some 
other  elastic  substance,  to  enable  the  rod  to  work  freely  up 
and  down,  without  permitting  the  escape  of  steam 

31 


362  APPENDIX, 

The  pipe  P,  which  is  called  the  steam-pipe, 
cates  with  the  boiler,  and  is  destined  to  convey  the  steam 
to  the  barrel  V  U  S  T.  It  is  divided  into  two  branches, 
each  of  which  may  be  closed  or  opened  by  means  of  cocks 
or  valves  placed  in  L  and  M,  so  as  to  admit  the  steam 
either  below  or  above  the  piston,  according  as  the  piston 
is  to  rise  or  to  descend  in  the  barrel. 

On  the  opposite  side  of  the  cylinder  there  is  a  similar 
tube  W,  called  the  edttefton-pipe,  likewise  divided  into  two 
branches,  and  communicating  with  the  barrel  in  U  and  T. 
This  pipe  is  intended  for  the  discharge  of  steam  after  it 
has  raised  or  forced  down  the  piston,  and  is,  in  O  and  N, 
provided  with  valves,  which  may  be  opened  or  closed,  ac- 
cording as  we  wish  to  discharge  the  steam  from  above  or 
below  the  piston,  viz  :  when  the  valve  O  is  opened  the 
steam  will  be  discharged  from  above  the  piston  ;  and  when 
the  valve  N  is  opened,  the  steam  will  escape  from  below  it. 

The  eduction  pipe  W,  is  conducted  into  what  is  called 
the  condenser  C.  This  is  a  vessel  destined  for  the  con- 
densation of  the  discharged  steam.  It  must  for  this 
purpose  be  constantly  kept  cool,  which  is  effected  by  sur- 
rounding it  with  cold  water,  or  placing  it  in  a  cistern  — 
the  cold  water  well  —  filled  with  water.  To  promote  the 
rapid'  condensation  of  the  steam  a  stream  of  cold  water  is 
constantly  discharged  into  the  condenser. 

The  pump  Q,,  which  in  its  construction  is  similar  to  a 
common  pump  (see  Natural  Philosophy,  Chapter  V),  is  a 
very  essential  part  of  the  low-pressure  steam  engine.  By  a 
mechanical  contrivance  it  is  connected  with,  and  worked 
by  the  rising  and  descending  of  the  piston  rod,  and  serves 
for  the  important  purpose  of  creating  a  constant  vacuum 
by  freeing  the  condenser  from  air  and  water  as  fast  as  the 
steam  is  discharged  into  it.  Without  this  pump  the  con- 
denser would  soon  be  filled  with  air  and  water,  and  the  dis- 
charge of  the  steam  be  rendered  impossible,  which  would 
arrest  the  operation  of  the  whole  machine.  This  mode  of 
creating  a  vacuum,  is  one  of  the  chief  improvements  of  the 
steam  engine,  for  which  we  are  indebted  to  James  Watt, 
a  celebrated  English  engineer,  whose  merits  in  this  branch 
of  the  arts  have  entitled  him  to  the  gratitude  of  the  age. 


APPENDIX.  363 

$  397.  When  the  machine  is  to  be  set  in  operation, 
the  water  in  the  boiler  is  heated  by  the  furnace,  and  by 
that  means  converted  into  steam.  The  four  valves,  L,  M, 
N,  O,  are  then  all  opened,  so  as  to  admit  the  steam  from 
the  boiler,  above  and  below  the  piston,  and  at  the  same 
time  to  allow  its  escape  into  the  condenser,  and  from 
thence  through  the  valve  of  the  pump  Q,  into  the  open  air. 
The  object  of  this  is  to  expel  the  air  from  every  part  of  the 
machine,  in  order  to  create  a  vacuum  by  the  subsequent  con- 
densation of  steam.  This  process  is  called  blowing  through. 
When  this  is  done,  the  valves  M  and  O  are  closed,  in 
order  to  admit  the  steam  only  above  the  piston,  through 
the  valve  L,  and  to  allow  the  escape  of  it  from  below  the  pis- 
ton, through  N  and  the  eduction  pipe  U,  into  the  condens- 
er. This  forces  the  piston  down  to  the  bottom  of  the  barrel, 
and  imparts  the  first  motion  to  the  engine.  The  valves  L 
and  N  are  now  closed,  and  O  and  M  opened.  By  this 
means  the  steam  from  the  boiler  is,  through  M  and  S,  admit- 
ted below  the  piston,  while  the  steam  above  the  piston  is 
permitted  to  escape  through  the  valve  O,  into  the  condenser. 
The  effect  of  this  operation  is  the  forcing  up  of  the  piston  to 
the  top  of  the  barrel.  The  valves  M  and  O,  being  again 
closed  in  their  turn,  and  L  and  N  opened,  a  fresh  portion 
of  steam  from  the  boiler  forces  the  piston  down  again  to 
the  bottom  of  the  barrel ;  and  so  does  the  alternate  open- 
ing and  closing  of  the  valves  M,  O,  and  N,  L,  respectively, 
admit  the  steam  below  or  above  the  piston,  and  produces 
the  moving  up  and  down  of  the  piston  rod,  by  which  means 
the  whole  machinery  is  set  in  motion. 

The  construction  of  the  engine  is  commonly  such  that 
the  closing  and  opening  of  the  valves,  as  well  as  the  work- 
ing of  the  air  pump  Q,  is  effected  by  levers  connected 
with  a  piston-rod ;  and  a  portion  of  the  power  of  the  engine 
is  therefore  always  expended  in  working  these  parts. 

The  pressure  of  the  steam  is  averaged  to  be  151bs.  to  the 
square  inch,  and  is  therefore  proportional  to  the  surface  of 
the  piston,  or  the  surface  of  a  parallel  section  of  the  barrel. 
Thus  a  pressure  of  several  hundred  horse  power  may  be 
produced  if  the  barrel  be  only  wide  enough  for  this  purpose. 

EXAMPLE.  If  the  horizontal  diameter  of  the  barrel  were 
3  feet,  the  area  of  a  sector  would,  according  to  the  rules  of 


364 


APPENDIX. 


geometry,*  be  1017.8784  square  inches,  and  the  pressure 
of  the  steam  1 5,268  Ibs !  If  the  horizontal  diameter  of  the 
cylinder  were  6  feet,  then  the  pressure  would  amount  to 
61,072  Ibs. !  and  so  on.  We  see  from  this  that  we  can  at 
pleasure  increase  or  decrease  the  power  of  the  engine  by 
widening  or  contracting  the  barrel  and  piston,  provided  the 
materials  are  strong  enough  to  resist  the  force  of  the  steam. 
For  in  proportion  to  the  pressure  of  the  steam,  the  piston 
will  be  moved  up  and  down  with  a  greater  or  less  force  ; 
which,  therefore,  ought  to  be  regulated  according  to  the 
purpose  for  which  the  engine  is  constructed. 

§  398.  If  the  motion  to  be  produced  by  the  machine  is 
rolary,  as  is,  for  instance,  the  case  in  the  construction  of 
steam-boats,  then  it  is  only  necessary  to  connect  the  piston- 
rod  with  one  end  of  a  lever,  and  the  wheel  which  is  to  be 
turned,  with  the  other,  as  is  represented  in  the  adjoining 
figure. 

Fig.  CXXXVII. 


B 


The  moving  up  and  down  of  the  piston,  sets  the  lever 
A  B,  in  motion,  which  in  its  turn  moves  the  wheel  W,  in 


*  The  area  of  a  circle  is  found  by  multiplying  the  squares  of  the 
radius  by  the  number  31.1416.     (See  Gruad's  Geometry  4  Part  I)» 


APPENDIX. 


365 


the  same  manner  as  a  grindstone  is  turned  by  a  crank 
moved  by  the  motion  of  the  foot.  If  the  motion  to  be 
communicated  is  to  act  perpendicular  or  horizontal,  then 
this  is  effected  by  a  system  of  levers  constructed  in  various 
ways,  and  the  operation  of  which  is  easily  understood  by 
the  inspection  of  the  machine. 

From  what  we  have  thus  far  explained,  the  learner  will 
be  able  to  understand  how  the  elastic  force  of  steam  is  ca- 
pable of  setting  a  complicated  machine  in  motion,  and 
that  this  force  may  be  increased  to  an  almost  infinite  extent, 
transcending  by  far  the  effects  produced  by  any  other  agent 
in  nature.  We  will  now  proceed  to  explain  separately 
the  construction  and  use  of  the  safety-valve,  and  the  manner 
in  which  the  valves  L  M,  N  O,  are  alternately  opened  and 
closed  by  the  operation  of  the  machine  itself;  after  which 
we  shall  give  a  short  description  of  Watt's  low-pressure 
engine,  now  commonly  used  for  propelling  steam-boats. 
Fig.  CXXXVIII, 


366  APPENDIX. 

§  399.  Fig.  CXXXVIII  represents  separately  the  boil- 
er and  safety-valve  of  a  steam  engine.  The  valve  V,  as  may 
be  seen  from  the  figure,  is  shaped  conically,  and  connected 
with  a  lever  C  D,  which,  in  D,  is  charged  with  a  small  weight 
W,  to  keep  the  valve  down.  This  weight  may  be  moved 
further  from,  or  nearer  to  the  valve,  according  as  we  wish 
the  steam  in  the  boiler  to  attain  a  greater  or  less  degree  of 
elasticity.  When  it  is  moved  nearer  the  fulcrum  C,  it 
will,  according  to  the  law  of  the  lever,  require  less  force  to 
lift  it  (to  open  the  valve)  than  when  it  is  removed  further 
from  it. 

Now,  the  elasticity  of  the  steam  in  the  low-pressure  en- 
gine being  equal  to  about  15  Ibs.  to  the  square  inch,  we 
can  easily  compute  the  pressure  which  it  will  exercise  up- 
on the  lower  surface  of  the  valve  ;  to  counteract  which  it 
will  only  be  necessary  to  depress  the  valve  with  a  power 
equal  to  the  same  weight.  But  for  this  purpose  we  need 
not  attach  any  weight  to  the  lever  C  D  ;  because  the  at- 
mosphere itself  has  that  power  (Natural  Philosophy,  Chap. 
V) ;  the  valve,  therefore,  without  the  weight,  could  not 
be  opened  until  the  elasticity  and  consequent  pressure  of 
the  steam  should  exceed  15  pounds  to  the  square  inch.  It 
is,  nevertheless,  necessary  to  attach  a  small  additional 
weight  (not  more  than  two  or  three  Ibs.)  to  the  lever  C  D, 
in  order  to  increase  the  elasticity  of  the  steam  in  the  boil- 
er to  a  degree  which  enables  it  to  blow  out  with  sufficient 
force  to  prevent  the  admission  of  atmospheric  air  into  the 
machine. 

§  400.  We  will  now  mention  an  improvement  of  Mr 
Murray's,  consisting  in  what  is  called  a  single  slide,  in- 
stead of  the  valves  for  the  admission  and  escape  of  steam. 
It  consists,  as  may  be  seen  from  the  following  two  figures, 
CXXXIX  and  CXL,  in  a  slide  S,  capable  of  being  moved 
up  and  down  in  the  direction  from  L  to  M,  which  is 


APPENDIX. 
Fig.  CXXXIX. 


367 


368  APPENDIX. 

effected  by  means  of  the  levers  M  N  O,  and  an  excentric, 
which  is  moved  by  the  turning  of  the  wheel,  as  is  repre- 
sented in  Fig.  CXLI,  page  369.  The  construction 
of  the  machine  is  such  that  when  the  slide  is  in  the 
position  represented  in  Fig.  CXXXIX,  the  steam  from 
the  boiler  is  admitted  through  the  steam  pipe  P,  into  the 
pipe  q  r,  and  thence  through  the  opening  u,  into  the  lower 
part  ty  of  the  barrel.  The  piston  will,  in  this  case,  be 
forced  up  to  the  extremity  of  the  barrel,  while  the  steam 
from  above  the  piston  is  discharged  through  a  b  d  n  o  e,  into 
the  condenser  C.  The  next  turn  of  the  wheel  places  the 
slide  S,  in  the  position  represented  in  Fig.  CXL.  The 
steam  from  the  boiler  is  now  prevented  from  entering  the 
pipe  q  r,  connected  with  the  lower  extremity  of  the  barrel  ; 
but  it  has  free  access  through  /  d)  into  the  pipe  a  6,  which 
conducts  it  to  the  upper  extremity  of  the  barrel.  This 
will  have  a  tendency  to  force  the  piston  down,  provided 
the  steam  from  below  the  piston  can  find  its  way  into  the 
condenser.  But  this  is  actually  provided  for  by  the  pipe 
t  u  r  q,  which  is  now  open  in  n,  and  admits  of  the  steam 
passing  through  o  e,  into  the  condenser.* 

We  see  from  these  figures  how  the  motion  of  the  piston 
rod  itself,  acting  on  the  levers  and  the  wheel,  may  serve 
to  open  and  close  the  valves,  and  how,  by  a  proper  ar- 
rangement of  the  different  parts  of  the  engine,  one  may  be 
made  to  act  upon  the  other,  so  that  the  very  power  which 
sets  the  engine  in  motion,  is  in  its  turn,  governed  by  the 
motion  of  which  it  is  the  cause. 

§  401.  The  next  figure  shows  the  construction  of  the 
different  parts  of  the  engine,  and  the  manner  in  which 
they  are  all  worked  by  the  simple  motion  of  the  piston  rod . 
After  what  has  gone  before,  the  learner  will  find  no  difficulty 
in  understanding  the  various  arrangements  of  the  machine. 

*  The  two  last  figures,  as  well  as  Fig.  CXLI,  are  copies  of  Mr 
Claxton's  models  of  the  steam  engine.  The  apparatus  itself  appears 
to  be  remarkably  simple,  and  eminently  calculated  to  give  a  clear 
and  distinct  idea  of  the  essential  parts  of  this  important  machine.  Mr 
Claxton  is  one  of  the  most  skilful  mechanics  in  Boston,  and  has  con- 
structed a  variety  of  physical  and  chemical  apparatus,  well  answering 
the  purposes  of  illustration  in  schools. 


APPENDIX. 


309 


Fig.  CXLT  represents  the  connexion  between  the 
different  parts  of  the  engine  we  have  just  described. 

B  represents  the  boiler. 

C  represents  the  safety  valve. 

F,  E  are  what  mechanics  call  steam  and  water  gauges 
respectively.  They  consist  of  hollow  tubes  provided  with 
stop-cocks.  The  gauge  F,  as  may  be  seen  from  the  figure, 
has  its  lower  end  immersed  in  the  water  :  but  the  gauge  E, 
does  not  communicate  with  the  surface  of  the  liquid. 
When  the  stop-cock  of  the  gauge  E  is  opened,  nothing  but 
steam  must  rush  forth,  otherwise  it  is  a  sign  that  there  is 
too  much  water  in  the  boiler  ;  but  when  the  stop-cock  of 
the  gauge  F  is  opened,  no  steam  must  pass,  else  it  is  a 
sign  that  the  water  is  too  high. 

M  represents  the  cylinder  or  barrel. 


370  APPENDIX. 

N  O  the  piston  and  piston-rod, 

P  represents  the  steam-pipe,  conducting  the  steam  from 
the  boiler  alternately  above  and  below  the  piston, 

S  represents  Murray's  single  slide,  by  the  motion  of 
which  the  steam  is  alternately  admitted  and  discharged 
from  the  barrel, 

K  represents  the  condenser,  enclosed  in  the  water  well, 

A  represents  the  beam  or  lever,  moved  up  and  down  by 
the  piston  rod, 

Q,  represents  the  air-pump,  worked  by  the  beam  or 
lever, 

H  the  wheel,  and 

G  represents  the  governor.  This  is  opened  or  closed 
by  the  centrifugal  force  produced  by  the  revolution  of  the 
fly  wheel  (see  Natural  Philosophy,  Chap.  1),  and  is  con- 
nected with  a  kind  of  valve  in  the  steam  pipe,  so  that  when 
it  opens  widest,  that  is,  when  the  wheel  turns  fastest,  it 
partly  closes  the  communication  between  the  boiler  and  the 
barrel,  by  which  means  a  smaller  quantity  of  steam  passes 
into  the  cylinder,  and  causes  the  engine  to  work  more 
slowly.  The  object  of  the  governor,  or  regulator  is,  there- 
fore, none  other  than  to  introduce  greater  regularity  into 
the  working  of  the  machine  by  regulating  the  quantity  of 
steam  passing  into  the  barrel. 

Finally,  R  represents  the  crank  rod,  which  gives  motion 
to  the  wheel. 

The  remainder  of  the  construction,  as  represented  in  the 
engraving,  is  sufficiently  plain  from  inspection,  and  from 
the  previous  explanation  of  its  parts. 

§  402.  Before  we  conclude,  it  behooves  us  to  say  a 
few  words  on  the  difference  between  low  pressure  and  high 
pressure  engines. 

The  high  pressure  engine  is  one  which  has  neither  con- 
denser nor  air-pump,  but  in  which  the  steam  from  above 
or  below  the  piston  is  immediately  discharged  into  the  at- 
mosphere. No  vacuum,  therefore,  is  created  in  the  barrel, 
and  the  atmosphere  having  always  access  to  that  surface 
of  the  piston  which  is  opposite  to  the  steam,  exercises  on 
that  side  a  pressure  of  15  Ibs.  on  the  square  inch.  This 
pressure  of  atmospheric  air  must  be  overcome  by  the 


APPENDIX.  37| 

steam,  in  addition  to  the  power  which  it  needs  for  setting 
the  machinery  in  motion  ;  and  it  will,  therefore,  require  a 
much  greater  elasticity  of  steam  to  set  a  high  pressure  en- 
gine in  motion,  than  is  needed  for  a  low  pressure  engine. 
For  while. a  steam  pressure  of  15  Ibs.  on  the  square  inch 
is  amply  sufficient  for  all  the  operations  of  a  low  press- 
ure engine  (with  condenser  and  air-pump),  a  pressure  of 
steam,  equal,  at  least,  to  15  Ibs.  on  the  square  inch  is  re- 
quired in  the  high  pressure  engine,  merely  to  counter- 
act the  pressure  of  the  atmosphere ;  and  the  machine, 
therefore,  can  only  work  with  the  surplus  of  power  which 
it  has  over  the  atmosphere.  The  principal  advantage  of  a 
low  pressure  engine  consists,  therefore,  in  the  complete  ex- 
clusion of  atmospheric  air,  which  is  effected  by  the  conden- 
ser and  the  air-pump.  But  the  high  pressure  engine  occu- 
pies less  space,  and  when  its  boiler  and  barrel  are  sufficient- 
ly strong,  can  exercise  a  powerful  pressure  with  very  little 
steam.  Besides  this,  the  water  with  which  it  is  necessary 
to  surround  the  condenser  of  the  low  pressure  engine  can- 
not always  be  readily  procured  ;  or  the  room  in  which  the 
machine  is  to  work  does  not  admit  of  its  presence.  In  all 
these  cases  high  pressure  engines  are  employed  in  prefer- 
ence to  low  pressure  engines  ;  and  it  is  on  this  account, 
principally,  that  they  are  exclusively  used  in  the  construc- 
tion of  locomotives. 


QUESTIONS  ON  THE  STEAM  ENGINE. 

[^  394.]  What  is  a  machine  called  in  which  the 
elasticity  of  steam  is  the  moving  force  ? 

[§  395.]  By  what  power  is  the  piston  moved  up,  in 
the  atmospheric  engine  ?  By  what  power  is  it  forced 
down  again,  when  a  vacuum  is  created  under  the  piston  ? 
What  does  this  kind  of  engine  require  after  each  stroke  of 
the  piston  ? 

[§  396.]     Explain  Fig.  CXXXVI.     What  is  the  use 


372  APPENDIX. 

of  the  safety  valve  ?  What  that  of  the  stuffing-box  1  What 
is  the  use  of  the  steam-pipe  ?  What  that  of  the  valves  re- 
presented in  the  figure  1  What  office  has  the  eduction  pipe  ? 
In  what  consists  the  use  of  the  condenser  ?  How  must  the 
condenser  constantly  be  kept  for  this  purpose  ?  What  is 
the  use  of  the  cold  water  well  ?  What  is  the  use  of  the 
pump  ?  What  would  soon  take  place  if  this  pump  ceased 
to  work  1 

[Sj  397.]  What  is  the  first  step  taken  in  order  to  set  the 
engine  to  work  ?  What  is  the  process  you  have  just  de- 
scribed, called  ?  What  rs  the  next  step  in  order  to  move  the 
piston  down  again  ?  By  what  means  is  the  piston  after- 
wards raised  again  to  the  top  of  the  barrel  ? 

What  is  the  average  pressure  of  steam  on  the  square 
inch  in  the  low  pressure  engine  ?  By  what  means  may  we, 
at  pleasure,  increase  or  diminish  the  power  of  this  engine  ? 

[$}  398.]  By  what  means  does  the  motion  of  the  piston 
rod  communicate  motion  to  the  other  parts  of  the  machine  ? 
Explain  Fig.  CXXXVII. 

[§  399.]  Explain  Fig.  CXXXVIII.  How  must  the 
safety  valve  be  shaped  ?  What  is  the  pressure  of  the 
steam  on  the  lower  surface  of  the  valve  1  What  is  the  ave- 
rage pressure  of  the  atmosphere  on  the  exterior  surface 
of  the  valve  equal  to  1  For  what  purpose  is  an  additional 
weight  attached  to  the  lever  1 

[&  400.]  Explain  Murray's  single  slide,  represented  in 
Figs.  CXXXIX  and  CXL. 

[§  401.]     Explain  the  different  parts  of  the  steam  en- 
gine, as  represented  in  Fig.  CXLI  ? 
What  does  B  represent  ? 
What,  C  D 1 

What  is  the  use  of  the  steam  and  water  gauges  ? 
Where  is  the  barrel  represented  ? 
Where,  the  piston-rod  ? 
Which  is  the  steam  pipe  ? 
Where  is  the  single  slide  ? 
Where  is  the  condenser  represented  ? 
What  is  the  object  of  the  governor  or  regulator  ? 


APPENDIX.  373 

402.]  In  what  respect  does  the  construction  of  the 
high  pressure  engine  differ  from  that  of  the  low  pressure 
engine  ?  Does  the' high  pressure  engine  require  more  or 
less  elasticity  of  steam,  to  be  set  in  motion,  than  the  low 
pressure  engine  ?  Why  ?  In  what,  therefore,  consists  the 
principal  advantage  of  the  low  pressure  engine '?  What, 
on  the  contrary,  are  the  advantages  of  the  high  pressure 
engines  ?  What  sort  of  engines  are  used  for  locomotives  ? 


374 


APPENDIX. 


TABLE  II. 

SCALE  OF  CHEMICAL  EQUIVALENTS  (OR  ATOMIC   WEIGHTS), 
In  which  hydrogen  gas  is  taken  for  unity,  after  Berzelius. 


Oxygen, 

8 

Gold, 

66 

Hydrogen, 

1 

Platinum, 

48 

Chlorine, 

35.4 

Palladium, 

56 

Nitrogen, 

14 

Rhodium, 

120 

Carbon, 

6 

Iridium, 

(?) 

Sulphur, 

16 

Osmium, 

(?) 

Silenium, 

40 

Nickel, 

29.5 

Phosphorus, 

16 

Iron, 

28 

Boron, 

16(?) 

Lead/ 

104 

Iodine, 

125 

Tin, 

59 

Bromine, 

(?) 

Copper, 

32 

Silicon, 

7.4 

Zinc,  (?) 

32.2 

Fluorine, 

18.6 

Bismuth, 

71 

Potassium, 

39.2 

Cobalt, 

29.5 

Sodium, 

23.3 

Antimony, 

64.5 

Lithium, 

8 

Arsenic, 

37.6 

Calcium, 

20.5 

Manganese, 

28 

Barium, 

68.6 

Tellurium, 

32.2 

Strontium, 

44 

Titanium, 

31 

Magnesium, 

12 

Cerium, 

46 

Glucinum, 

18 

Uranium, 

217 

Yttrium, 

32 

Columbium, 

184 

Allumium, 

9 

Tungsten, 

96 

Zirconium, 

22.4 

Cadmium, 

56 

Thorium, 

(?) 

Chromium, 

28 

Mercury, 

101 

Molybdenum, 

48 

Silver, 

108 

Vanadium, 

(?) 

INDEX. 


A. 

Acid,  iodic,       - 

157 

lactic, 

337 

Acetate  of  Lead,  - 

317 

malic,     - 

313 

Acetates, 
Acetous  fermentation, 

S17 

352 

manganesic, 
molybdic, 

224 
228 

Acids,  definition  of,     - 
General  remarks  on, 

38 
247 

molybdous,  - 
mucous, 

228 
337 

Acid,  acetic, 

316 

muriatic, 

106 

animal,  - 

336 

nitric, 

99 

antimonious, 

221 

nitrous, 

93 

arsenic, 

223 

nitro-muriatic,    - 

202 

arsenious,     • 

223 

olific, 

336 

benzoic 

315 

oxalic,     - 

314 

bitumous,     - 

315 

pectic, 

314 

boletic,   - 

316 

phosphoric, 

152 

boracic, 

155 

phosphorous, 

151 

bromic,  - 

159 

prussic,  - 

136 

camphoric,  - 

307 

saccholactic, 

337 

carbonic, 

127 

silenic,    - 

149 

chloric, 

105 

succinic, 

316 

chromic, 

228 

sulphuric,        ^  •    . 

143 

citric, 

313 

sulphurous,  - 

142 

cyanic,    • 

135 

tartaric,  - 

312 

cyanous,    ,;-^. 

135 

tungstic, 

226 

fluoric,    - 

307 

vegetable, 

312 

fulminic, 

289 

Acidifying  principle, 

248 

formic,   - 

337 

Action,  chemical,        • 

4 

gallic, 
hydriotic, 

314 
157 

Affinity,    - 
elective, 

4 

7 

hydro-bromic, 

159 

double  elective,   - 

9 

hydro-bromous, 

159 

predisposing,  • 

9 

hydro-cyanic, 

136 

Agate, 

160 

hydro-fluoric,      - 

162 

Air,  atmospheric, 

88 

hydro-phosphoric,    - 

152 

Alabaster, 

275 

hydro-sulphuric, 

144 

Alcohol, 

309 

liypo-nitrous, 

97 

Alembic,  • 

21 

376 


INDEX. 


Alizarine,        -  319 

Albumen,  vegetable,        -  321 

animal,        -  331 

Alkalies,  -                        -  180 

Alkaline  metals,  179 

Alkali,  vegetable,              -  183 

volatile,  102 

Alloys  of  metals,  -            -  177 

Aloes,               -  308 

Alumium,              -             -  193 

Alumine,  sulphate  of,  -  279 

Alum,  -  -  279 
Amalgams,  -  -  177,196 
Amathyst,  194, 161 

Amatto,  319 

Amber,  308 

Ammonia,                         -  101 

liquid,           -  101 

nitrate  of,           -  263 

carbonate  of,  280 

phosphate  of,     -  285 

muriate  of,  -  268 

Analysis,  chemical,  2 

Animal  chemistry,      -  329 

substances,           -  330 

acids,              -  336 

charcoal,               -  124 

jelly,  -  331 

gluten  (fibrin)      -  341 

mucus,  335 

oils  and  fat,           -  335 

albumen,        -  331 

coverings,             -  343 

Antimony,       -  220 
per-oxide,  deutox- 
ide,  and  protoxide 

of,       -             -  221 

Proto- chloride  of  222 

Anthracite  coal,           -  123 

Apparatus,  chemical,         -  17 
for  dividing  bodies,  17 
for   separating  li- 
quids from  solids,    18 
for  the  liquefaction 

of  solids,     -  20 
for    evaporation 
and  crystaliza- 

tion,           -  21 

for  distillation,  21 
for  heating  animal 

substances     -  23 


Apparatus  for  compressing 
bodies  or  extract- 
ing liquids  from 
solids,  •  27 

for  collecting  gas- 
es,    -  -        30 
for  various  chem- 
ical purposes,         31 
A  phlogistic  lamp,               -      205 
Aqua  fortis,      -  99 
regia,           -            -      109 
Aqueous  fusion,                       254 
Arsenic,    - 

A  rseniuretted  hydrogen,          223 
Arsenites,  -       287 

Arsenite  of  potash,       -  288 

of  cobalt,  -       288 

Asafetida,       -  -  308 

Attraction,  chemical,        -          2 
Azote,  -  -  87 


B 


Balance,  common,       -  33 
per  cent, 

portable,        -  33 
Baldwin's  phosphorus       -  263 
Balloon,                         -  67 
Barium,    -                          -  188 
protoxide  of  baryta,  188 
Bases,  38 
from  the  mineral  king- 
dom,                       -  252 
organic,  252 
Basic  salts,             -             -  253 
Bell  glass,        -             -  30 
Bile,                                <*.w  338 
Bismuth,                   '""»•'•  219 
oxide  of,               -  220 
chloride  of,    -  220 
Bitter  salt,            -             -  275 
Black  and  brown  coal,  123 
Black  oxide  of  manganese,  224 
Blood,  332 
Blow-pipe,                          -  25 
oxy-hydrogen,  70 
with  condensed  oxy- 

fn  and  hydrogen,  72 
277 

Boiling  of  liquids,        -  80 

Bone  black,           -            -  124 


INDEX. 


377 


Bones, 

341 

Chemical  affinity,  - 

2 

Borax,      - 

155 

apparatus,     - 

17 

Boron,              -             * 

155 

analysis, 

2 

Brass,        ... 

217 

combination, 

2 

Brain,  substance  of,     - 
Bristles,    - 

340 
344 

composition  of  bodies 
equivalents,    • 

,36 
14 

Bromine, 

158 

ingredients, 

13 

Butter,      - 

334 

proportions,     - 

10 

of  antimony, 

222 

separation,          -    j 

3 

Chlorates, 

266 

C. 

Chlorate  of  potash, 

266 

of  soda, 

268 

Cadmium, 
Calcium,  - 

227 

187 

hydro  of  ammonia, 
Chlorides, 

268 
270 

oxide  of, 

187 

Chloride  of  calcium, 

188 

Calomel,  - 

198 

of  cobalt, 

273 

Camwood, 

319 

of  copper,         217, 

272 

Camphor, 

307 

of  gold, 

271 

Caoutchouc,     - 

308 

of  lead,    -        214, 

272 

Carbon,     - 

122 

of  lime, 

269 

with  chlorine,  - 
Carbonic  oxide,     - 

138 
125 

of  magnesium,    - 
of  mercury, 

191 

198 

with  sulphur,     - 

139 

of  nitrogen, 

109 

Sulphuretof 

140 

of  platinum,  - 

271 

Carbonates, 

280 

of  potassium, 

184 

Carbonate  of  ammonia,    - 

280 

of  silver, 

201 

of  potash,  - 

281 

of  sodium, 

185 

of  soda, 

281 

of  strontium, 

189 

of  magnesia, 

282 

of  thorium, 

195 

of  lime, 

282 

of  tin      -          216, 

272 

of  baryta, 

283 

Chlorine, 

103 

of  lead, 

283 

combination  of,  - 

104" 

ofiron, 

284 

protoxide  of,  - 

104 

of  copper,  - 

284 

per-oxide  of, 

105 

Carburet?, 

176 

Chromates, 

286 

Carbureted  hydrogen, 

133 

Chromate  of  potash, 

287 

sub, 

130 

of  lead,        -   - 

287 

Cartilage, 

341 

of  mercury, 

287 

Cam  el  ion,                       *  *- 

161 

Chromium, 

227 

Caustic  lunar,  - 

264 

Chrysopras, 

161 

lye, 

184 

Chyle, 

339 

Cerium, 

225 

Cinnaber, 

199 

Chalcedon, 

161 

Claws,             -  * 

343 

Chalk,     - 

283 

Coal  gas,               -         '  -     :' 

134 

dampness,  - 

1.26 

Cobalt, 

220 

Charcoal,  vegetable,   - 
animal,  - 

123 
124 

Cocoa  butter, 
Cohesive  attraction,     - 

307 
6 

Cheese, 

334 

Coloring  matters, 

319 

Chemistry,  definition  of,  - 

2 

Combinations  in  fixed  pro- 

Chemical action, 

4 

portions,    '""M 

11 

32* 

378 


INDEX. 


Combinations,  chemical,  - 

2 

Element,     - 

4 

Combustion,  theory  of, 

52 

Elements,  nomenclature  of, 

c7 

in  oxygen, 

53 

Emerald, 

194 

Columbium,    - 

225 

Epsom  salts, 

275 

Common  Resin,    • 

308 

Equivalents,    - 

14 

Salt,  - 

186 

Essential  oils, 

306 

Complex  affinity,  - 

9 

Ether, 

310 

Congreve  Rockets, 

268 

sulphuric,     - 

311 

Copal,       - 

308 

Etching  on  glass, 

163 

Copper, 

216 

Eudiometry, 

90 

combinations  of,   - 

217 

Eudiometer,  Achard's, 

90 

proto-chloride  of, 

218 

by  detonating  ox- 

per-chloride of,    - 

218 

ygen   and  hy- 

Copperas, 

144 

drogen  gas, 

91 

Corrosive  sublimate, 

198 

Gay  Lussac's, 

92 

Cream, 

334 

Evaporation, 

-1 

of  tartar,     - 

312 

apparatus  for, 

21 

Cruor  of  the  blood, 

332 

Extinguishing  of  fire, 

58 

Cryophorus, 

82 

Extract,  vegetable, 

320 

Crystalography, 

254 

Crystal  mountain, 

313 

F. 

Cyanites, 

288 

Cyanuret  of  mercury, 
Cyanogen, 

135 
134 

Fats,  animal, 
Feathers, 

335 
344 

with  oxygen, 

135 

Fermentation, 

352 

with  hydrogen, 

135 

acetous, 
putrid, 

353 
355 

D. 

vinous,  - 

352 

Fermentous  principle, 

320 

Diamond, 

122 

Fernambucco  wood,    - 

319 

Decrepitation, 

254 

Fibrin, 

341 

Decomposition, 

3 

Fibre,  woody, 

304 

spontaneous, 

352 

Fire-damp, 

130 

Definite  proportions,    - 

11 

Fixed  air, 

126 

volumes,  - 

76 

Fixed.  oils, 

307 

Desoxidation,  - 
Deliquescence,     - 

59 
254 

vegetable  alkalies, 
proportions  and  ratios, 

302 
11 

Difference  between  organic 

Flint,        -                    ;;;i*. 

161 

and  inorganic  matter, 

300 

Fluorine, 

162 

Distillation  of  water, 

83 

other  combinations  of,  163 

Dragons'  blood, 

308 

Flowers  of  sulphur, 

141 

Dregs,      -        6^-..'.      :-,',; 

320 

zinc, 

219 

Fluoride  of  calcium, 

162 

E. 

Fluorides, 

176 

Fluor, 

160 

Earthy  metals, 

190 

Flux,  -        '*••'•-, 

179 

Efflorescence, 

254 

Frost  bearer,     ,  ~~j?£\ 

82 

Elective  affinity,  - 

7 

Fulminates,     - 

288 

double, 

9 

Fulminating  powder, 

261 

Electricity,  galvanic, 

250 

Furnace, 

23 

Electro-chemical  theory, 

14    Fustic,      - 

319 

INDEX 


379 


G. 

Horn  lead,       -            -            214 

silver,           -            -      201 

Galena,            -            -.          214 

Horns,              -            -            344 

Galvanic  electricity,         -         40 

Hydrates,              -            -      249 

Gamboge,        -                          308 

lydrate  of  potash,      -            183 

Gas,  Oxygen, 
hydrogen, 

lydro-chlorate  of  ammonia,    268 
Jydro-acids,   -          .  -            249 

carbonic  acid,            -       127 

lydrogen,                           -         59 

muriatic  acid,      "-            106 
light, 

lydrogen,  properties  of, 
mode  of  obtaining,   64 

olifiant,     -             -            133 

carbureted,      -      133 

nitrogen,        -             -         87 

sulphureted,           147 

Gases,  combina'n  by  volume,   76 

sub-carbureted,      130 

Gastric  juice, 

combination  with 

Gelatine, 

oxygen,       -         73 

Germination  of  seeds,       -       351 

deutoxide  of            8G 

Gilding,           -                         196 

mixture  with  oxy- 

Glass makers'  soap, 

gen,          *Jg        67 

Glass,  - 

gun,    - 

Glimmer,  - 

application  of           66 

Glucina,            -                           192 

-ivrfrous  state, 

Glucinum, 

rlypo-nitrous  aoid,       -              97 

Glue,  animal,  - 

Gluten,     -                         -       321 

I. 

Gold,   - 

combinations  of 

Ice,           •                                   77 

Granite, 
Graphit,    -                           -       123 

Immediate  ingredients  of  an- 
unals,     -             329 

Gravitation  of  integrant  mole- 

of vegetables,  302 

cules,          -             -      259 

Ink,  indelible  or  marking,       265 

Green  vitriol,  -                          278 
Gum,        - 

sympathetic, 
writing, 

ammonia, 

India  rubber,  - 

elastic,                        -       308 

Indigo,      - 

Gun  metal, 

Inflammable  air,          -    13j 

powder, 

gas,  - 

properties  Of, 
Gypsum,  -                          -       272 

Ingredients,     • 
Ingredients    of   the    animal 
body,            -      320 

H. 

Hair,         -             -   •         -       344 

Hare's  blow  pipe, 
Hartshorn, 
spirits  of,     - 

Inorganized  bodies}    • 
Inorganic  elements  of  plants,   3 
Instantaneous  light  matches,    267 
Integrant  moleciMes,        -      257 
Iodide  of  quicksilver,  - 
Iodine,  properties  of,         -       156 

Heat, 

with  carbon,      - 

effects  of, 
promoting  chemical  affin- 

with  hydrogen,       -       157 
with  oxygen,    - 

ity  j 

Iridium,    -            -            -      207 

Heavy  spar,     - 

Iron,    -            -            -            208 

Hoofs,       -                         '      34 

380 


INDEX. 


Iron,  combination  of, 
with  carbon, 
meteoric, 
protoxide  of, 
per-oxide  of,  - 
proto-chloride  of, 
per-chloride  of, 
sulphuret  of, 

Juice  of  grapes,    • 


Kelp,  - 
Kings'  water, 


K. 


L. 


208 
211 
208 
208 
209 
210 
210 
211 
302 


156 

202 


Lamp,       -  24 
furnace,  25 
safety,        -            -  131 
Lac  lake,          -             -  319 
Lard,         -             -             -337 
Lead,  -            -            -  212 
combination  with  oxy- 
gen,            -  213 
chloride  of,           -    '  214 
Lees,        -            -            -  320 
Lehigh  coal,    -            -  123 
Levity  of  hydrogen  gas,    -  63 
Life  and  death  of  animals,  800 
Lime,        -                         -  187 
stone,      -  283 
Ligaments,            -             -  343 
Light,  carbureted  hydrogen,  130 
Liquid  ammonia,  -             -  101 
sulphuric  acid,  -  144 
muriatic  acid,         -  108 
nitric  acid,        -  99 
Liquids  employed  in  the  pro- 
cess of  digestion,  338 
Litmus,     -             -             -  319 
Litharge,         -  214 
Lithium,  -             -  186 
Lithia,  187 
Loaf  sugar,         '.  •            -  306 
Lunar  caustic,  264 
Lutes,       -       ;"..  - ..V        -  35 
Lye, caustic,   -        ;. '.  .  184 


M. 


Malates, 


313 


Magnesia,             -            •  191 

Magnesium,    -            •  190 

Marble,    -            -            -  283 

Marrow,           -             -  342 

Manganese,          -            -  224 

oxide  of,    -  224 

chloride  of,     -  224 

Massicot,         -  214 

Membranes,          -             -  342 

Mercurial  ore,  195 

Mercury,              -            -  195 

properties  of,  195 

combination   with 

oxygen,       -  196 

protoxide  of,  197 

per-oxide  of,       -  197 

with  chlorine,  197 

with  sulphur,      -  199 

Metals,  classification  of,  179 

alloys  of,   -             -  177 

preliminary  remarks 

on,             -  175 
general  properties  of,  174 
reduction  of,          -  178 
refining,           -  177 
nomenclature  of,  -  175 
combining  with  oxy- 
gen,       -  175 
other  combinations  of,  176 
soldering  of,          -  177 
Meteoric  iron,     -         -  209 
Microcosmic  salt,  -            -  285 
Milk,  333 
sugar  of,         -             -  335 
Mineralizers,  -  178 
Mixtures  of  nitrogen  and  oxy- 
gen,             -  £9 
of  hydrogen  and  oxy- 
gen,       -  67 
Molasses,     -          -            -  306 
Molybdenum,  228 
Mucus,  animal,     -             -  335 
Muscles,                       -  342 
Muriates,               -            -  279 
Myrrh,             -  308 

N. 

Native  metals,             .  178 

Nerves,  substance  of,        -  340 

Neutralization,            -  6 


INDEX 


381 


Neutral  animal  substances,    83 
unsalifiable  vegetable 

substances,  30 

Neutral  salts,  -  25 

Nickel,     -                         -  20 

oxide  of,  20 

Nitrates,   -             -             -  25 

Nitrate  of  potash,        -  26 

of  sod a,       -  26 

of  ammonia,       -  26 

of  lime,       -             -  26; 

of  lead,  26i 

of  copper,  -             -  266 

of  mercury,       -  26 

of  silver,     -             -  26 

Nitre,  properties  of,     -  26( 

Nitrogen,  - 

combination    with 

oxygen,         -  92 

mixture  of,   -  88 

protoxide  of,       -  91 

deutoxide  of,  95 

with  hydrogen,  -  10 

Nomenclature  of  elements,  37 

of  acids, 

of  oxides,  51 

of  salts,  253 

Non-metallic  elements,  122 

Nooth's  apparatus,   -        -  129 

O. 

Oil  of  almonds,            -  307 

of  vitriol,         -             -  143 

olive,          -  307 

Olefiant  gas,          -             -  133 

application  of,  133 

Organic  chemistry,           -  300 

Organized  bodies,        -  300 

Organs,  '  -                          -  301 

Ores,   -                          -  178 

Osmazome,                         -  340 

Osmium,          -  207 

Oxalates,  -                           -  314 

Oxides,  definition  of,  -  38 

nomenclature  of,  -  51 

Oxidation,        -  175 

Oxygen,  properties  of,      -  50 

mode  of  obtaining,  50 

combination  of,  51 

combustion  of,     -  53 


Oxygenation  of  bodies,  -  61 

Oxygenized  water,  -        86 

P. 

Palladium,       -  -  206 

Pearlash,  -  .      133 

Phenomena  attending  acetous 

fermentation,    355 
attending  vinous 

fermentation,    353 
attending    putre- 
faction, 4$>      355 
Phlogiston  of  the  ancients,        52 
Phosphates,  .       284 

Phosphate  of  ammonia,  285 

of  soda,  -       285 

of  lime,       -  286 

Phosphorus,  -      149 

properties  of,  150 
with  oxygen,  151 
with  hydrogen,  152 
other  combina- 
tions of,  -  154 
Phosphureted  hydrogen,  153 
Plants,  nature  of,  -  48  -  300 
Plaster  stone,  -  275 

of  Paris,      -  275 

Platinum,        -  £  204 

sponge,  -  -      205 

lumbago,       -  123 

Dneumatic  tub,     -  30 

Potash,  -  183 

hydrate  of,  -      183 

3otassium,       -  180 

mode  of  obtaining,  181 
properties  of,y^  182 
combinations  with 

oxygen,  -       183 

chloride  of,     -  184 

Mmitive  form  of  crystals,      255 
>oducts  of  vegetables,  302 

'roportions,         &  -         11 

^rocess  of  nutrition  necessa- 
ry to  life,      -      351 
'rocess  of  putrefaction,  3J>5 

'russian  blue,  318 

russicacid,         -  136,  318 

umice,    -  -       161 

utrefaction  with  free  access 

of  air,      -      356 


382 


INDEX. 


Putrefaction  with  little  or  no 

Saturation,            -            -          8 

accessof  air, 

357 

Scale  of  equivalents,  -            374 

Putrid  fermentation  of  vege- 
tables, 

355 

Scales,      -                          -      -343 
Secondary  form  of  crystals,    255 

Pyrites, 

211 

Selenites,        -                         275 

Selenium,                          •      149 

Q. 

Selieneted  hydrogen,               149 

Serum,      -                          -       332 

Quar'z,     ... 

161 

Sheet  iron  tinning,      -             178 

Quaternary  combinations, 

247 

Silicious  earth,      -             -       161 

Quicksilver,     - 

195 

Silicides,          -                         176 

Silicon,      -            -             -       159 

R. 

Silex,  -             -                          160 

Silk,           -                          -      344 

Raw  sugar, 

306 

Silver, 

Realgar,   - 

224 

combinations  of,        -      200 

Receiver, 

22 

oxide  of,  -                        201 

Red  oxide  of  copper, 

217 

sulphuretof,  - 

Reduction  of  metals,   - 

178 

Silvering  of  looking-glasses,    196 

Refining  of  sugar, 
Remote  ingredients  of  plants. 

306 
302 

Simple  bodies,       -            -        37 
Skin,   -             -                          343 

Resins,      - 

303 

Slaking  lime,         -            -       187 

Respiration,     - 

330 

Smalts,            -             -             220 

Rete  mucosum,     - 

343 

Smelting  ores,      -            -      179 

Retort, 

22 

Soap,  -             -                          307 

Rhubarb,     S 

319 

Soda,         -             -             -       185 

Rhodium, 

207 

Sodium,                                    185 

Rock  or  mountain  crystal, 

161 

with  oxygen,        -       185 

Roll-brimstone, 

142 

protoxide  and  per-ox- 

Roasting  of  metals,       .    - 

179 

ide  of,        -            185 

Rotten  stone,  - 

161 

chloride  of,            -      186 

Rust  of  iron, 

176 

Solution,         -                             8 

Spar,         -             -            -       162 

S. 

Specific  gravity,  mode  of  de- 

* *  - 

termining,        -       34 

Safety  lamp, 

131 

Speculum  metal,          -            217 

Safflower, 

319 

Spermaceti,           -            -       336 

Saffron, 

319 

Spirit  of  hartshorn,      -             101 

Sal-ammoniac, 

101 

Spiritus  cornu  cervi,          -       331 

Salifiable  bases, 

252 

Spirituous  liquors,        -            309 

vegetable  bases, 
Saliva,       ... 

311 
338 

Sponge,  platinum,              -     -205 
Soldering  of  metals,     -             177 

Saltpetre,  uses  of, 

261 

Sorb  or  service  tree,          -      313 

Salts,  definition  of, 

249 

Sour  salts,       -                          253 

of  hartshorn,     - 

280 

Steam,      -                                   84 

common:  table, 

186 

principal  properties  of,    84 

smelling, 

280 

engine,              -            360 

Sanders'  wood,     - 

309 

Steel,        -             -             -      211 

Sand,  • 

161 

Strontia,          -            -            189 

Sandarach, 

308 

water,      -            -      189 

Sapphire, 

194 

Strontium.       -            -            189 

INDEX. 


383 


Succinates, 

316 

Tendons,          -            .            342 

Sugar,  - 

305 

Thoria,     -            -            .       195 

manufactory  of,    .    - 

306 

Thorium,         -                         195 

of  lead,  - 

317 

chloride  of   (     -      195 

of  milk, 
Sulphates, 
Sulphate'  of  potash, 

333 
273 
274 

Thornberry,  black,    £&       319 
Tin,          -            -    l       .      214 
salt,          -  ™                     272 

of  soda, 

274 

with  oxygen,                    215 

of  lime,  -' 
of  magnesia, 

275 
275 

chloride  of,           -            216 
Titanium,              -            -       225 

of  mercury, 

276 

Tombac,           -                         217 

of  silver, 

277 

Topaz,      -            -             -194 

of  copper, 

277 

Tripoli,            -     ;        .            161 

of  iron, 

278 

Tungsten,             -            -       226 

of  baryta, 

278 

Turf,  .                                        123 

of  ammonia,  • 

278 

Tumeric,    -                              319 

ofalumine, 

279 

Turpentine,     -                         308 

Sulphides, 

176 

- 

Sulphur,   • 

141 

U. 

properties  of,  - 
combinations  of,   - 
with  oxygen,  - 
Sulphuret  of  silver, 

nf  IpaH 

142 
142 
142 

201 
914. 

Ultimate  principles  of  plants,    303 
of  animals,  330 
Undetermined  vegetable  sub- 
stances,   t       -      318 

Ol  lead,              — 

of  iron,  - 

201,4 

211 

Unsaleable   vegetable   sub- 

of palladium, 
of  arsenic, 
of  tin, 

207 
224 
216 

stances,      -            303 
Uranium,  -                       -      226 
oxide  of,      \-            226 

of  antimony, 

222 

of  copper,    - 

218 

• 

of  carbon, 

139 

Vanadium,                               228 

of  strontium, 
of  mercury, 

189 
199 

Vapor,    refrigerating    influ- 
ence of,    V^ 

Sulphureted  hydrogen,    - 
Sulphuric  acid,  mode  of  pre- 

148 

Vegetable  chemistry,       -      300 
acids,           -    303,312 

paring, 

145 

alkali,  -            -       183 

Synthesis, 

2 

extract, 
composition  of,        303 

IA.              ^0R*               01  o 

T. 

salt,      •  e 

substances    of  an 

Table  salt, 

186 

undetermined  na- 

Tallow, 

335 

ture, 

Tan, 

314 

Venice-sumac,   f»           -      319 

Tartar, 

313 

Vermilion,       -  J                     199 

cream  of,   - 

312 

Vinous  fermentation,        •      352 

Tartrate  of  potash,       * 

313 

phenomena  accompa- 

Teeth,     • 

341 

nying, 

enamel  of 
Tellurium, 
Temperature    changed    by 
chemical  action,    - 

342 
225 

4 

Virgin  quicksilver,           •      195 
Vital  principle,                        301 
Vitriol,  oil  of,      C» 
green,         •        278,  144 

384 

INDEX. 

Vitriol,  blue,        -        ,  .*-  ,  ' 

277 

White  oxide  of  phosphorus, 

151 

Volatile  alkali, 

102 

Woad,       - 

319 

Volumes  of  gases, 

76 

Wollaston's  theory,     - 

258 

Wolfram,  - 

226 

W. 

Wool,   - 

344 

Woolf  s  apparatus, 

107 

Water,      - 

73 

composition  of,    - 

75 

Y. 

properties  of, 

76 

of  erystalization, 

254 

Yttrium,  - 

193 

expansion  in  freezing, 
boiling  of, 

77 
81 

oxide  of, 
Ytterby,   - 

193 
193 

baryta, 

188 

f- 

strontia, 

189 

Z. 

oxygenized, 
rain,  pump,  and  river, 
Jpurity  of,    - 
gilding, 
Watery  animal  substances, 
unsaJifiable  vegetable 
•/substances, 

86 
78 
85 
196 
330 

306 

Zaffre, 
Zinc,  - 
oxide  of, 
flowers  of, 
carbonate  of,  - 
chloride  of, 

319 
218 
219 
219 
219 
219 

Wax,  - 

309 

Zircon, 

194 

Weld 

319 

Zirconia, 

194 

Whale  oil,       - 

336 

Zirconium, 

194 

Wheat,     -  X        - 

321 

• 


^ 


Ik. 


. 


